Antagonists of pcsk9

ABSTRACT

Antagonists of human proprotein convertase subtilisin-kexin type 9 (“PCSK9”) are disclosed. The disclosed antagonists are effective in the inhibition of PCSK9 function and, accordingly, present desirable antagonists for the use in the treatment of conditions associated with PCSK9 activity. The present invention also discloses nucleic acid encoding said antagonists, vectors, host cells, and compositions comprising the antagonists. Methods of making PCSK9-specific antagonists as well as methods of using the antagonists for inhibiting or antagonizing PCSK9 function are also disclosed and form important additional aspects of the present disclosure.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application Nos.60/857,293 and 60/857,248, both filed on Nov. 7, 2006.

STATEMENT REGARDING FEDERALLY-SPONSORED R&D

Not Applicable.

REFERENCE TO MICROFICHE APPENDIX

Not Applicable.

BACKGROUND OF THE INVENTION

Proprotein convertase subtilisin-kexin type 9 (hereinafter called“PCSK9”), also known as neural apoptosis-regulated convertase 1(“NARC-1”), is a proteinase K-like subtilase identified as the 9^(th)member of the secretory subtilase family; see Seidah et al., 2003 PNAS100:928-933. The gene for PCSK9 localizes to human chromosome1p33-p34.3; Seidah et al., supra. PCSK9 is expressed in cells capable ofproliferation and differentiation including, for example, hepatocytes,kidney mesenchymal cells, intestinal ileum, and colon epithelia as wellas embryonic brain telencephalon neurons; Seidah et al., supra.

Original synthesis of PCSK9 is in the form of an inactive enzymeprecursor, or zymogen, of ˜72-kDa which undergoes autocatalytic,intramolecular processing in the endoplasmic reticulum (“ER”) toactivate its functionality. This internal processing event has beenreported to occur at the SSVFAQ↓SIPWNL¹⁵⁸ motif rendering the firstthree N-terminal residues Ser-Ile-Pro (Benjannet et al., 2004 J. Biol.Chem. 279:48865-48875), and has been reported as a requirement of exitfrom the ER; Benjannet et al., supra; Seidah et al., supra. The cleavedprotein is then secreted. The cleaved peptide remains associated withthe activated and secreted enzyme; supra.

The gene sequence for human PCSK9, which is ˜22-kb long with 12 exonsencoding a 692 amino acid protein, can be found, for example, at DepositNo. NP_(—)777596.2. Human, mouse and rat PCSK9 nucleic acid sequenceshave been deposited; see, e.g., GenBank Accession Nos.: AX127530 (alsoAX207686), AX207688, and AX207690, respectively.

PCSK9 is disclosed and/or claimed in several patent publicationsincluding, but not limited to the following: PCT Publication Nos. WO01/31007, WO 01/57081, WO 02/14358, WO 01/98468, WO 02/102993, WO02/102994, WO 02/46383, WO 02/90526, WO 01/77137, and WO 01/34768; USPublication Nos. US 2004/0009553 and US 2003/0119038, and EuropeanPublication Nos. EP 1 440 981, EP 1 067 182, and EP 1 471 152.

PCSK9 has been ascribed a role in the differentiation of hepatic andneuronal cells (Seidah et al., supra.), is highly expressed in embryonicliver, and has been strongly implicated in cholesterol homeostasis.Recent studies seem to suggest a specific role in cholesterolbiosynthesis or uptake. In a study of cholesterol-fed rats, Maxwell etal. found that PCSK9 was downregulated in a similar manner as threeother genes involved in cholesterol biosynthesis, Maxwell et al., 2003J. Lipid Res. 44:2109-2119. Interestingly, as well, the expression ofPCSK9 was regulated by sterol regulatory element-binding proteins(“SREBP”), as seen with other genes involved in cholesterol metabolism;supra. These findings were later supported by a study of PCSK9transcriptional regulation which demonstrated that such regulation wasquite typical of other genes implicated in lipoprotein metabolism; Dubucet al., 2004 Arterioscler. Thromb. Vasc. Biol. 24:1454-1459. PCSK9expression was upregulated by statins in a manner attributed to thecholesterol-lowering effects of the drugs; supra. More, the PCSK9promoters possessed two conserved sites involved in cholesterolregulation, a sterol regulatory element and an Sp1 site; supra.Adenoviral expression of PCSK9 has been shown to lead to a notabletime-dependent increase in circulating LDL (Benjannet et al., 2004 J.Biol. Chem. 279:48865-48875). More, mice deleted of the PCSK9 gene haveincreased levels of hepatic LDL receptors and more rapidly clear LDLfrom the plasma; Rashid et al., 2005 Proc. Natl. Acad. Sci. USA102:5374-5379. Recently it was reported that medium from HepG2 cellstransiently transfected with PCSK9 reduced the amount of cell surfaceLDLR and internalization of LDL when transferred to untransfected HepG2cells; see Cameron et al., 2006 Human Mol. Genet. 15:1551-1558. It wasconcluded that either PCSK9 or a factor acted upon by PCSK9 is secretedand is capable of degrading LDLR both in transfected and untransfectedcells. More recently, it was demonstrated that purified PCSK9 added tothe medium of HepG2 cells had the effect of reducing the number ofcell-surface LDLRs in a dose- and time-dependent manner; Lagace et al.,2006 J. Clin. Invest. 116:2995-3005.

A number of mutations in the gene PCSK9 have also been conclusivelyassociated with autosomal dominant hypercholesterolemia (“ADH”), aninherited metabolism disorder characterized by marked elevations of lowdensity lipoprotein (“LDL”) particles in the plasma which can lead topremature cardiovascular failure; see Abifadel et al., 2003 NatureGenetics 34:154-156; Timms et al., 2004 Hum. Genet. 114:349-353; Leren,2004 Clin. Genet. 65:419-422. A later-published study on the S127Rmutation of Abifadel et al., supra, reported that patients carrying sucha mutation exhibited higher total cholesterol and apoB100 in the plasmaattributed to (1) an overproduction of apoB100-containing lipoproteins,such as low density lipoprotein (“LDL”), very low density lipoprotein(“VLDL”) and intermediate density lipoprotein (“IDL”), and (2) anassociated reduction in clearance or conversion of said lipoproteins;Ouguerram et al., 2004 Arterioscler. Thromb. Vasc. Biol. 24:1448-1453.

Together, the studies referenced above evidence the fact that PCSK9plays a role in the regulation of LDL production. Expression orupregulation of PCSK9 is associated with increased plasma levels of LDLcholesterol, and inhibition or the lack of expression of PCSK9 isassociated with low LDL cholesterol plasma levels. Significantly, lowerlevels of LDL cholesterol associated with sequence variations in PCSK9have conferred protection against coronary heart disease; Cohen, 2006 N.Engl. J. Med. 354:1264-1272

The identification of compounds and/or agents effective in the treatmentof cardiovascular affliction is highly desirable. Reductions in LDLcholesterol levels have already demonstrated in clinical trials to bedirectly related to the rate of coronary events; Law et al., 2003 BMJ326:1423-1427. More, recently moderate lifelong reduction in plasma LDLcholesterol levels has been shown to be substantially correlated with asubstantial reduction in the incidence of coronary events; Cohen et al.,supra. This was found to be the case even in populations with a highprevalence of non-lipid-related cardiovascular risk factors; supra.Accordingly, there is great benefit to be reaped from the managedcontrol of LDL cholesterol levels.

Accordingly, it would be of great import to produce a therapeutic-basedantagonist of PCSK9 that inhibits or antagonizes the activity of PCSK9and the corresponding role PCSK9 plays in various therapeuticconditions.

SUMMARY OF THE INVENTION

The present invention relates to antagonists of PCSK9 and particularlyhuman PCSK9. Protein-specific antagonists of PCSK9 (or “PCSK9-specificantagonists” as referred to herein) are PCSK9 protein-specific bindingmolecules or proteins effective in the inhibition of PCSK9 functionwhich are of import in the treatment of conditions associated with orimpacted by PCSK9 function, including, but not limited tohypercholesterolemia, coronary heart disease, metabolic syndrome, acutecoronary syndrome and related conditions. PCSK9-specific antagonists arecharacterized by selective recognition and binding to PCSK9.PCSK9-specific antagonists do not show significant binding to other thanPCSK9, other than in those specific instances where the antagonist issupplemented to confer an additional, distinct specificity to thePCSK9-specific binding portion. In specific embodiments, PCSK-9 specificantagonists bind to human PCSK9 with a KD of 1.2×10-6 or less. Inspecific embodiments, PCSK9-specific antagonists bind to human PCSK9with a KD of 1×10-7 or less. In additional embodiments, PCSK9-specificantagonists bind to human PCSK9 with a KD of 1×10-8 or less. In otherembodiments, PCSK9-specific antagonists bind to human PCSK9 with a KD of5×10-9 or less, or of 1×10-9 or less. In further embodiments,PCSK9-specific antagonists bind to human PCSK9 with a KD of 1×10-10 orless, a KD of 1×10-11 or less, or a KD of 1×10-12 or less. In specificembodiments, PCSK9-specific antagonists do not bind other proteins atthe above levels.

PCSK9-specific antagonists are effective in counteractingPCSK9-dependent inhibition of cellular LDL-uptake. Repeatedly,PCSK9-specific antagonists demonstrate dose-dependent inhibition of theeffects of PCSK9 on LDL uptake. Accordingly, PCSK9-specific antagonistsare of import for lowering plasma LDL cholesterol levels. Saidantagonists also have utility for various diagnostic purposes in thedetection and quantification of PCSK9.

In specific embodiments, the present invention encompassesPCSK9-specific antagonists, and, in specific embodiments, antibodymolecules, comprising disclosed heavy and/or light chain variableregions, equivalents having one or more conservative amino acidsubstitutions, and homologs thereof. Particular embodiments compriseisolated PCSK9-specific antagonists that comprise disclosed CDR domainsor sets of the heavy and/or light chain CDR domains, and equivalentsthereof characterized as having one or more conservative amino acidsubstitutions. As will be appreciated by those skilled in the art,fragments of PCSK9-specific antagonists that retain the ability toantagonize PCSK9 may be inserted into various frameworks, see, e.g.,U.S. Pat. No. 6,818,418 and references contained therein which discussvarious scaffolds which may be used to display antibody loops previouslyselected on the basis of antigen binding. In the alternative, genesencoding for VL and VH may be joined, using recombinant methods, forexample using a synthetic linker that enables them to be made as asingle protein chain in which the VL and VH regions pair to formmonovalent molecules, otherwise known as single chain Fvs (“ScFVs”);see, e.g., Bird et al., 1988 Science 242: 423-426, and Huston et al.,1988 Proc. Natl. Acad. Sci. USA 85:5879-5883.

PCSK-9 specific antagonists and fragments may be in the form of variousnon-antibody-based scaffolds, including but not limited to avimers(Avidia); DARPins (Molecular Partners); Adnectins (Adnexus), Anticalins(Pieris) and Affibodies (Affibody). The use of alternative scaffolds forprotein binding is well appreciated in the scientific literature, see,e.g., Binz & Plückthun, 2005 Curr. Opin. Biotech. 16:1-11. Accordingly,non-antibody-based scaffolds or antagonist molecules with selectivityfor PCSK9 that counteract PCSK9-dependent inhibition of cellularLDL-uptake form important embodiments of the present invention.

In another aspect, the present invention provides nucleic acid encodingdisclosed PCSK9-specific antagonists. The present invention provides, inparticular aspects, nucleic acid encoding PCSK9-specific antagonists,and in specific embodiments, disclosed antibody molecules, whichcomprise disclosed variable heavy and light regions and selectcomponents thereof, particularly the disclosed respective CDR3 regions.In another aspect, the present invention provides vectors comprisingsaid nucleic acid. In another aspect, the present invention providesisolated cells) comprising nucleic acid encoding disclosedPCSK9-specific antagonists, in specific embodiments, disclosed antibodymolecules and components thereof as described. In another aspect, thepresent invention provides isolated cell(s) comprising a polypeptide, orvector of the present invention.

In another aspect, the present invention provides a method of makingPCSK9-specific antagonists which selectively bind PCSK9 including butnot limited to antibodies, antigen binding fragments, derivatives,chimeric molecules, fusions of any of the foregoing with anotherpolypeptide, or alternative structures/compositions capable ofspecifically binding PCSK9. The method comprises incubating a cellcomprising nucleic acid encoding the PCSK9-specific antagonist(s), orcomprising individual nucleic acids encoding one or more componentsthereof, said nucleic acids, which when expressed, collectively producethe antagonist(s), under conditions that allow for the expression and/orassembly of the PCSK9-specific antagonist(s), and isolating saidantagonist(s) from the cell. One of skill in the art can obtainPCSK9-specific antagonists disclosed herein as well using standardrecombinant DNA techniques.

In another aspect, the present invention provides a method forantagonizing the activity or function of PCSK9, or a noted effect ofPCSK9, which comprises contacting a cell, population of cells, or tissuesample of interest expressing PCSK9 (or treated with PCSK9) with aPCSK9-specific antagonist disclosed herein under conditions that allowsaid antagonist to bind to PCSK9. Specific embodiments of the presentinvention include such methods wherein the cell is a human cell.Antagonists in accordance herewith are effective in the inhibition ofPCSK9 function. Disclosed PCSK9-specific antagonists were found to dosedependently inhibit the effects of PCSK9 on LDL uptake.

In another aspect, the present invention provides a method forantagonizing the activity of PCSK9 in a subject exhibiting a conditionassociated with PCSK9 activity, or a condition where the functioning ofPCSK9 is contraindicated for a particular subject, which comprisesadministering to the subject a therapeutically effective amount of aPCSK9-specific antagonist of the present invention. In selectembodiments, the condition may be hypercholesterolemia, coronary heartdisease, metabolic syndrome, acute coronary syndrome or relatedconditions. In another aspect, the present invention provides apharmaceutical composition or other composition comprising aPCSK9-specific antagonist of the invention and a pharmaceuticallyacceptable carrier, excipient, diluent, stabilizer, buffer, oralternative designed to facilitate administration of the antagonist inthe desired amount to the treated individual.

The present invention also relates to a method for identifying PCSK9antagonists in a cell sample which comprises providing purified PCSK9and labeled LDL particles to a cell sample; providing a molecule(s)suspected of being a PCSK9 antagonist to the cell sample; incubating thecell sample for a period of time sufficient to allow LDL particle uptakeby the cells; isolating cells of the cell sample by removing thesupernate; reducing non-specific association of labeled LDL particles;lysing the cells; quantifying the amount of label retained within thecell lysate; and identifying those candidate antagonists that result inan increase in the amount of quantified label as compared with thatobserved when PCSK9 is administered alone. Candidate antagonists thatresult in an increase in the amount of quantified label are PCSK9antagonists. This method has proven to be an effective means foridentifying PCSK9-specific antagonists and, thus, forms an importantaspect of the present invention.

The following table offers a generalized outline of the sequencesdiscussed in the present application:

TABLE 1 SEQ ID NO: DESCRIPTION SEQ ID NO: 1 LIGHT CHAIN (“LC”); 1CX1G08SEQ ID NO: 2 LC NUCLEIC ACID; 1CX1G08 SEQ ID NO: 3 VL CDR1; 1CX1G08 SEQID NO: 4 VL CDR1 NUCLEIC ACID; 1CX1G08 SEQ ID NO: 5 VL CDR2; 1CX1G08;3BX5C01 SEQ ID NO: 6 VL CDR2 NUCLEIC ACID; 1CX1G08; 3BX5C01 SEQ ID NO: 7VL CDR3; 1CX1G08 SEQ ID NO: 8 VL CDR3 NUCLEIC ACID; 1CX1G08 SEQ ID NO: 9Fd CHAIN; 1CX1G08 SEQ ID NO: 10 Fd CHAIN NUCLEIC ACID; 1CX1G08 SEQ IDNO: 11 VH; 1CX1G08 SEQ ID NO: 12 VH NUCLEIC ACID; 1CX1G08 SEQ ID NO: 13VH CDR1; 1CX1G08 SEQ ID NO: 14 VH CDR1 NUCLEIC ACID; 1CX1G08 SEQ ID NO:15 VH CDR2; 1CX1G08 SEQ ID NO: 16 VH CDR2 NUCLEIC ACID; 1CX1G08 SEQ IDNO: 17 VH CDR3; 1CX1G08 SEQ ID NO: 18 VH CDR3 NUCLEIC ACID; 1CX1G08 SEQID NO: 19 LIGHT CHAIN (“LC”); 3BX5C01 SEQ ID NO: 20 LC NUCLEIC ACID;3BX5C01 SEQ ID NO: 21 VL CDR1; 3BX5C01 SEQ ID NO: 22 VL CDR1 NUCLEICACID; 3BX5C01 SEQ ID NO: 23 VL CDR3; 3BX5C01 SEQ ID NO: 24 VL CDR3NUCLEIC ACID; 3BX5C01 SEQ ID NO: 25 Fd CHAIN; 3BX5C01 SEQ ID NO: 26 FdCHAIN NUCLEIC ACID; 3BX5C01 SEQ ID NO: 27 VH; 3BX5C01 SEQ ID NO: 28 VHNUCLEIC ACID; 3BX5C01 SEQ ID NO: 29 VH CDR1; 3BX5C01 SEQ ID NO: 30 VHCDR1 NUCLEIC ACID; 3BX5C01 SEQ ID NO: 31 VH CDR2; 3BX5C01 SEQ ID NO: 32VH CDR2 NUCLEIC ACID; 3BX5C01 SEQ ID NO: 33 VH CDR3; 3BX5C01 SEQ ID NO:34 VH CDR3 NUCLEIC ACID; 3BX5C01 SEQ ID NO: 35 LIGHT CHAIN (“LC”);3CX2A06 SEQ ID NO: 36 LC NUCLEIC ACID; 3CX2A06 SEQ ID NO: 37 VL CDR1;3CX2A06 SEQ ID NO: 38 VL CDR1 NUCLEIC ACID; 3CX2A06 SEQ ID NO: 39 VLCDR2; 3CX2A06; 3CX3D02 SEQ ID NO: 40 VL CDR2 NUCLEIC ACID; 3CX2A06;3CX3D02 SEQ ID NO: 41 VL CDR3; 3CX2A06 SEQ ID NO: 42 VL CDR3 NUCLEICACID; 3CX2A06 SEQ ID NO: 43 Fd CHAIN; 3CX2A06 SEQ ID NO: 44 Fd CHAINNUCLEIC ACID; 3CX2A06 SEQ ID NO: 45 VH; 3CX2A06 SEQ ID NO: 46 VH NUCLEICACID; 3CX2A06 SEQ ID NO: 47 VH CDR1; 3CX2A06 SEQ ID NO: 48 VH CDR1NUCLEIC ACID; 3CX2A06 SEQ ID NO: 49 VH CDR2; 3CX2A06 SEQ ID NO: 50 VHCDR2 NUCLEIC ACID; 3CX2A06 SEQ ID NO: 51 VH CDR3; 3CX2A06 SEQ ID NO: 52VH CDR3 NUCLEIC ACID; 3CX2A06 SEQ ID NO: 53 LIGHT CHAIN (“LC”); 3CX3D02SEQ ID NO: 54 LC NUCLEIC ACID; 3CX3D02 SEQ ID NO: 55 VL CDR1; 3CX3D02SEQ ID NO: 56 VL CDR1 NUCLEIC ACID; 3CX3D02 SEQ ID NO: 57 VL CDR3;3CX3D02 SEQ ID NO: 58 VL CDR3 NUCLEIC ACID; 3CX3D02 SEQ ID NO: 59 FdCHAIN; 3CX3D02 SEQ ID NO: 60 Fd CHAIN NUCLEIC ACID; 3CX3D02 SEQ ID NO:61 VH; 3CX3D02 SEQ ID NO: 62 VH NUCLEIC ACID; 3CX3D02 SEQ ID NO: 63 VHCDR1; 3CX3D02 SEQ ID NO: 64 VH CDR1 NUCLEIC ACID; 3CX3D02 SEQ ID NO: 65VH CDR2; 3CX3D02 SEQ ID NO: 66 VH CDR2 NUCLEIC ACID; 3CX3D02 SEQ ID NO:67 VH CDR3; 3CX3D02 SEQ ID NO: 68 VH CDR3 NUCLEIC ACID; 3CX3D02 SEQ IDNO: 69 LIGHT CHAIN (“LC”); 3CX4B08 SEQ ID NO: 70 LC NUCLEIC ACID;3CX4B08 SEQ ID NO: 71 VL CDR1; 3CX4B08 SEQ ID NO: 72 VL CDR1 NUCLEICACID; 3CX4B08 SEQ ID NO: 73 VL CDR2; 3CX4B08 SEQ ID NO: 74 VL CDR2NUCLEIC ACID; 3CX4B08 SEQ ID NO: 75 VL CDR3; 3CX4B08 SEQ ID NO: 76 VLCDR3 NUCLEIC ACID; 3CX4B08 SEQ ID NO: 77 Fd CHAIN; 3CX4B08 SEQ ID NO: 78Fd CHAIN NUCLEIC ACID; 3CX4B08 SEQ ID NO: 79 VH; 3CX4B08 SEQ ID NO: 80VH NUCLEIC ACID; 3CX4B08 SEQ ID NO: 81 VH CDR1; 3CX4B08 SEQ ID NO: 82 VHCDR1 NUCLEIC ACID; 3CX4B08 SEQ ID NO: 83 VH CDR2; 3CX4B08 SEQ ID NO: 84VH CDR2 NUCLEIC ACID; 3CX4B08 SEQ ID NO: 85 VH CDR3; 3CX4B08 SEQ ID NO:86 VH CDR3 NUCLEIC ACID; 3CX4B08 SEQ ID NO: 87 IgG2m4 SEQ ID NO: 88IgG2m4 NUCLEIC ACID SEQ ID NO: 89 Contains IgG1 Fc SEQ ID NO: 90Contains IgG2 Fc SEQ ID NO: 91 Contains IgG4 Fc SEQ ID NO: 92 ContainsIgG2m4 Fc SEQ ID NO: 93 VL; 1CX1G08 SEQ ID NO: 94 VL NUCLEIC ACID;1CX1G08 SEQ ID NO: 95 VL; 3BX5C01 SEQ ID NO: 96 VL NUCLEIC ACID; 3BX5C01SEQ ID NO: 97 VL; 3CX2A06 SEQ ID NO: 98 VL NUCLEIC ACID; 3CX2A06 SEQ IDNO: 99 VL; 3CX3D02 SEQ ID NO: 100 VL NUCLEIC ACID; 3CX3D02 SEQ ID NO:101 VL; 3CX4B08 SEQ ID NO: 102 VL NUCLEIC ACID; 3CX4B08

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates Fab expression vector pMORPH_x9_MH.

FIG. 2 illustrates how the potencies of PCSK9 mutants in Exopolarcorrelate with plasma LDL-cholesterol.

FIGS. 3A-3D illustrate 1CX1G08's and 3CX4B08's dose-dependent inhibitionof PCSK9-dependent effects on LDL uptake. FIGS. 3B and 3D have twocontrols: (i) a cell only control, showing the basal level of cellularLDL uptake, and (ii) a cell+PCSK9 (25 μg/ml) control which shows thelevel of PCSK9-dependent loss of LDL-uptake. The titration experimentswhich contain Fab and PCSK9 were done at a fixed concentration of PCSK9(25 μg/ml) and increasing concentrations of Fab shown in the graphs.FIGS. 3A and 3C show calculations of IC-50s.

FIGS. 4A-4D illustrate 3BX5C01's and 3CX2A06's dose-dependent inhibitionof PCSK9-dependent effects on LDL uptake. FIGS. 4B and 4D have twocontrols: (i) a cell only control, showing the basal level of cellularLDL uptake, and (ii) a cell+PCSK9 (25 μg/ml) control which shows thelevel of PCSK9-dependent loss of LDL-uptake. The titration experimentswhich contain Fab and PCSK9 were done at a fixed concentration of PCSK9(25 μg/ml) and increasing concentrations of Fab shown in the graphs.FIGS. 4A and 4C show calculations of IC-50s.

FIGS. 5A-5B illustrate 3CX3D02's dose-dependent inhibition ofPCSK9-dependent effects on LDL uptake. FIG. 5B has two controls: (i) acell only control, showing the basal level of cellular LDL uptake, and(ii) a cell+PCSK9 (25 μg/ml) control which shows the level ofPCSK9-dependent loss of LDL-uptake. The titration experiment whichcontains Fab and PCSK9 was done at a fixed concentration of PCSK9 (25μg/mL) and increasing concentrations of Fab shown in the graph. FIG. 5Ashows calculations of IC-50.

FIG. 6 illustrates a sequence comparison of the Fc domains of IgG1(residues 24-353 of SEQ ID NO: 89), IgG2 (residues 7-332 of SEQ ID NO:90), IgG4 (residues 7-333 of SEQ ID NO: 91) and the IgG2m4 (residues7-332 of SEQ ID NO: 92) isotypes.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to antagonists of PCSK9 and particularlyhuman PCSK9. Protein-specific antagonists of PCSK9 (or “PCSK9-specificantagonists”) in accordance herewith are effective in the inhibition ofPCSK9 function and, thus, are of import in the treatment of conditionsassociated with/impacted by PCSK9 function, including, but not limitedto, hypercholesterolemia, coronary heart disease, metabolic syndrome,acute coronary syndrome and related conditions. Reference herein toPCSK9 function or PCSK9 activity refers to any activity/function thatrequires, or is exacerbated or enhanced by PCSK9. PCSK9-specificantagonists have been demonstrated herein to be particularly effectivefor counteracting PCSK9-dependent inhibition of cellular LDL-uptake.Repeatedly, disclosed antagonists demonstrated dose-dependent inhibitionof the effects of PCSK9 on LDL uptake.

PCSK9-specific antagonists as disclosed herein are, therefore, desirablemolecules for lowering plasma LDL cholesterol levels. PCSK9-specificantagonists are of utility for any primate, mammal or vertebrate ofcommercial or domestic veterinary importance. PCSK9-specific antagonistsare of utility as well for any population of cells or tissues possessingthe LDL receptor. Means for measuring LDL uptake and, thus, variouseffects thereon are described in the literature; see, e.g., Barak &Webb, 1981 J. Cell Biol. 90:595-604, and Stephan & Yurachek, 1993 J.Lipid Res. 34:325330. In addition, means for measuring LDL cholesterolin plasma is well described in the literature; see, e.g., McNamara etal., 2006 Clinica Chimica Acta 369:158-167.

PCSK9-specific antagonists also have utility for various diagnosticpurposes in the detection and quantification of PCSK9.

PCSK9-specific antagonists as defined herein selectively recognize andspecifically bind to PCSK9. Use of the terms “selective” or “specific”herein refers to the fact that the disclosed antagonists do not showsignificant binding to other than PCSK9, except in those specificinstances where the antagonist is supplemented to confer an additional,distinct specificity to the PCSK9-specific binding portion (as, forexample, in bispecific or bifunctional molecules where the molecule isdesigned to bind or effect two functions, at least one of which is tospecifically bind PCSK9). In specific embodiments, PCSK9-specificantagonists bind to human PCSK9 with a KD of 1.2×10-6 or less. Inspecific embodiments, PCSK9-specific antagonists bind to human PCSK9with a KD of 5×10-7 or less, of 2×10-7 or less, or of 1×10-7 or less. Inadditional embodiments, PCSK9-specific antagonists bind to human PCSK9with a KD of 1×10-8 or less. In other embodiments, PCSK9-specificantagonists bind to human PCSK9 with a KD of 5×10-9 or less, or of1×10-9 or less. In further embodiments, PCSK9-specific antagonists bindto human PCSK9 with a KD of 1×10-10 or less, a KD of 1×10-11 or less, ora KD of 1×10-12 or less. In specific embodiments, PCSK9-specificantagonists do not bind other proteins at the above KDs. KD refers tothe dissociation constant obtained from the ratio of Kd (thedissociation rate of a particular binding molecule-target proteininteraction) to Ka (the association rate of the particular bindingmolecule-target protein interaction), or Kd/Ka which is expressed as amolar concentration (M). KD values can be determined using methods wellestablished in the art. A preferred method for determining the KD of abinding molecule is by using surface plasmon resonance, for example abiosensor system such as a Biacore™ (GE Healthcare Life Sciences)system.

PCSK9-specific antagonists have been shown to dose-dependently inhibitPCSK9 dependent effects on LDL uptake. Accordingly, PCSK9-specificantagonists are characterized by their ability to counteractPCSK9-dependent inhibition of LDL uptake into cells. This uptake of LDLinto cells by the LDL receptor is referred to herein as “cellular LDLuptake”. In specific embodiments, PCSK9-specific antagonists antagonizePCSK9-dependent inhibition of LDL uptake into cells, exhibiting an IC50of 1.2×10-6 or less. In specific embodiments, PCSK9-specific antagonistsantagonize PCSK9-dependent inhibition of LDL uptake into cells,exhibiting a KD of 5×10-7 or less, of 2×10-7 or less, or of 1×10-7 orless. In additional embodiments, PCSK9-specific antagonists antagonizePCSK9-dependent inhibition of LDL uptake into cells, exhibiting an IC50of 1×10-8 or less. In other embodiments, PCSK9-specific antagonistsantagonize PCSK9-dependent inhibition of LDL uptake into cells,exhibiting an IC50 of 5×10-9 or less, of 2×10-9 or less, or of 1×10-9 orless. In further embodiments, PCSK9-specific antagonists antagonizePCSK9-dependent inhibition of LDL uptake into cells, exhibiting an IC50of 1×10-10 or less, a KD of 1×10-11 or less, or a KD of 1×10-12 or less.The extent of inhibition by any PCSK9-specific antagonist may bemeasured quantitatively in statistical comparison to a control, or viaany alternative method available in the art for assessing a negativeeffect on, or inhibition of, PCSK9 function (i.e., any method capable ofassessing antagonism of PCSK9 function). In specific embodiments, theinhibition is at least about 10% inhibition. In other embodiments, theinhibition is at least 20%, 30%, 40%, 50%, 60%, 70,%, 80%, 90%, or 95%.

A PCSK9-specific antagonist in accordance herewith can be any bindingmolecule with specificity for PCSK9 protein including, but not limitedto, antibody molecules as defined below, any PCSK9-specific bindingstructure, any polypeptide or nucleic acid structure that specificallybinds PCSK9, and any of the foregoing incorporated into various proteinscaffolds; including but not limited to, various non-antibody-basedscaffolds, and various structures capable of affording selective bindingto PCSK9 including but not limited to small modularimmunopharmaceuticals (or “SMIPs”; see, Haan & Maggos, 2004 BiocenturyJanuary 26); Immunity proteins (see, e.g., Chak et al., 1996 Proc. Natl.Acad. Sci. USA 93:6437-6442); cytochrome b562 (see Ku and Schultz, 1995Proc. Natl. Acad. Sci. USA 92:6552-6556); the peptide α2p8 (see Bartheet al., 2000 Protein Sci. 9:942-955); avimers (Avidia; see Silverman etal., 2005 Nat. Biotechnol. 23:1556-1561); DARPins (Molecular Partners;see Binz a al., 2003 J. Mol. Biol. 332:489-503; and Forrer et al., 2003FEBS Lett. 539:2-6); Tetranectins (see, Kastrup et al., 1998 Acta.Crystallogr. D. Biol. Crystallogr. 54:757-766); Adnectins (Adnexus; see,Xu et al., 2002 Chem. Biol. 9:933-942), Anticalins (Pieris; see Vogt &Skerra, 2004 Chemobiochem. 5:191-199; Beste et al., 1999 Proc. Natl.Acad. Sci. USA 96:1898-1903; Lamla & Erdmann, 2003 J. Mol. Biol.329:381-388; and Lamla & Erdmann, 2004 Protein Expr. Purif. 33:39-47);A-domain proteins (see North & Blacklow, 1999 Biochemistry38:3926-3935), Lipocalins (see Schlehuber & Skerra, 2005 Drug Discov.Today 10:23-33); Repeat-motif proteins such as Ankyrin repeat proteins(see Sedgwick & Smerdon, 1999 Trends Biochem. Sci. 24:311-316; Mosavi etal., 2002 Proc. Natl. Acad. Sci. USA 99:16029-16034; and Binz et al.,2004 Nat. Biotechnol. 22:575-582); Insect Defensin A (see Zhao et al.,2004 Peptides 25:629-635); Kunitz domains (see Roberts et al., 1992Proc. Natl. Acad. Sci. USA 89:2429-2433; Roberts et al., 1992 Gene121:9-15; Dennis & Lazarus, 1994 J. Biol. Chem. 269:22129-22136; andDennis & Lazarus, 1994 J. Biol. Chem. 269:22137-22144); PDZ-Domains (seeSchneider et al., 1999 Nat. Biotechnol. 17:170-175); Scorpion toxinssuch as Charybdotoxin (see Vita et al., 1998 Biopolymers 47:93-100);10^(th) fibronectin type III domain (or 10Fn3; see Koide et al., 1998 J.Mol. Biol. 284:1141-1151, and Xu et al., 2002 Chem. Biol. 9:933-942);CTLA-4 (extracellular domain; see Nuttall et al., 1999 Proteins36:217-227; and Irving et al., 2001 J. Immunol. Methods 248:31-45);Knottins (see Souriau et al., 2005 Biochemistry 44:7143-7155 and Lehtioet al., 2000 Proteins 41:316-322); Neocarzinostatin (see Heyd et al.2003 Biochemistry 42:5674-5683); carbohydrate binding module 4-2(CBM4-2; see Cicortas et al., 2004 Protein Eng. Des. Set 17:213-221);Tendamistat (see McConnell & Hoess, 1995 J. Mol. Biol. 250:460-470, andLi et al., 2003 Protein Eng. 16:65-72); T cell receptor (see Holler etal., 2000 Proc. Natl. Acad. Sci. USA 97:5387-5392; Shusta et al., 2000Nat. Biotechnol. 18:754-759; and Li et al., 2005 Nat. Biotechnol.23:349-354); Affibodies (Affibody; see Nord et al., 1995 Protein Eng.8:601-608; Nord et al., 1997 Nat. Biotechnol. 15:772-777; Gunneriussonet al., 1999 Protein Eng. 12:873-878); and other selective bindingproteins or scaffolds recognized in the literature; see, e.g., Binz &Plückthun, 2005 Curr. Opin. Biotech. 16:1-11; Gill & Damle, 2006 Curr.Opin. Biotechnol. 17:1-6; Hosse et al., 2006 Protein Science 15:14-27;Binz et al., 2005 Nat. Biotechnol. 23:1257-1268; Hey et al., 2005 Trendsin Biotechnol. 23:514-522; Binz & Plückthun, 2005 Curr. Opin. Biotech.16:459-469; Nygren & Skerra, 2004 J. Immunolog. Methods 290:3-28; Nygren& Uhlen, 1997 Curr. Opin. Struct. Biol. 7:463-469. Antibodies and theuse of antigen-binding fragments is well defined in the literature. Theuse of alternative scaffolds for protein binding is well appreciated inthe scientific literature as well, see, e.g., Binz & Plückthun, 2005Curr. Opin. Biotech. 16:1-11; Gill & Damle, 2006 Curr. Opin. Biotechnol.17:1-6; Hosse et al., 2006 Protein Science 15:14-27; Binz et al., 2005Nat. Biotechnol. 23:1257-1268; Hey et al., 2005 Trends in Biotechnol.23:514-522; Binz & Plückthun, 2005 Curr. Opin. Biotech 16:459-469;Nygren & Skerra, 2004 J. Immunolog. Methods 290:3-28; Nygren & Uhlen,1997 Curr. Opin. Struct. Biol. 7:463-469. Accordingly,non-antibody-based scaffolds or antagonist molecules with selectivityfor PCSK9 that counteract PCSK9-dependent inhibition of cellularLDL-uptake form important embodiments of the present invention. Aptamers(nucleic acid or peptide molecules capable of selectively binding atarget molecule) are one specific example. They can be selected fromrandom sequence pools or identified from natural sources such asriboswitches. Peptide aptamers, nucleic acid aptamers (e.g., structurednucleic acid, including both DNA and RNA-based structures) and nucleicacid decoys can be effective for selectively binding and inhibitingproteins of interest; see, e.g., Hoppe-Seyler & Butz, 2000 j. Mol. Med.78:426-430; Bock et al., 1992 Nature 355:564-566; Bunka & Stockley, 2006Nat. Rev. Microbiol. 4:588-596; Martell et al., 2002 Molec. Ther.6:30-34; Jayasena, 1999 Clin. Chem. 45:1628-1650.

Expression and selection of various PCSK9-specific antagonists may beachieved using suitable technologies including, but not limited to phagedisplay (see, e.g., International Application Number WO 92/01047, Kay etal., 1996 Phage Display of Peptides and Proteins: A Laboratory Manual,San Diego: Academic Press), yeast display, bacterial display, T7display, and ribosome display (see, e.g., Lowe & Jermutus, 2004 Curr.Pharm. Biotech. 517-527).

“Antibody molecule” or “Antibody” as described herein refers to animmunoglobulin-derived structure with selective binding to PCSK9including, but not limited to, a full length or whole antibody, anantigen binding fragment (a fragment derived, physically orconceptually, from an antibody structure), a derivative of any of theforegoing, a chimeric molecule, a fusion of any of the foregoing withanother polypeptide, or any alternative structure/composition whichincorporates any of the foregoing for purposes of selectivelybinding/inhibiting the function of PCSK9. “Whole” antibodies or “fulllength” antibodies refer to proteins that comprise two heavy (H) and twolight (L) chains inter-connected by disulfide bonds which comprise: (1)in terms of the heavy chains, a variable region (abbreviated herein as“V_(H)”) and a heavy chain constant region which comprises threedomains, C_(H1), C_(H2), and C_(H3); and (2) in terms of the lightchains, a light chain variable region (abbreviated herein as “V_(L)”)and a light chain constant region which comprises one domain, C_(L).

“Isolated” as used herein describes a property as it pertains to thedisclosed PCSK9-specific antagonists, nucleic acid or other that makesthem different from that found in nature. The difference can be, forexample, that they are of a different purity than that found in nature,or that they are of a different structure or form part of a differentstructure than that found in nature. A structure not found in nature,for example, includes recombinant human immunoglobulin structuresincluding, but not limited to, recombinant human immunoglobulinstructures with optimized CDRs. Other examples of structures not foundin nature are PCSK9-specific antagonists or nucleic acid substantiallyfree of other cellular material. Isolated PCSK9-specific antagonists aregenerally free of other protein-specific antagonists having differentprotein specificities (i.e., possess an affinity for other than PCSK9).

Antibody fragments and, more specifically, antigen binding fragments aremolecules possessing an antibody variable region or segment thereof(which comprises one or more of the disclosed CDR 3 domains, heavyand/or light), which confers selective binding to PCSK9, andparticularly human PCSK9. Antibody fragments containing such an antibodyvariable region include, but are not limited to the following antibodymolecules: a Fab, a F(ab′)₂, a Fd, a Fv, a scFv, bispecific antibodymolecules (antibody molecules comprising a PCSK9-specific antibody orantigen binding fragment as disclosed herein linked to a secondfunctional moiety having a different binding specificity than theantibody, including, without limitation, another peptide or protein suchas an antibody, or receptor ligand), a bispecific single chain Fv dimer,an isolated CDR3, a minibody, a ‘scAb’, a dAb fragment, a diabody, atriabody, a tetrabody, a minibody, and artificial antibodies based uponprotein scaffolds, including but not limited to fibronectin type IIIpolypeptide antibodies (see, e.g., U.S. Pat. No. 6,703,199 andInternational Application Numbers WO 02/32925 and WO 00/34784) orcytochrome B; see, e.g., Nygren et al., 1997 Curr. Opinion Struct. Biol.7:463-469. The antibody portions or binding fragments may be natural, orpartly or wholly synthetically produced. Such antibody portions can beprepared by various means known by one of skill in the art, including,but not limited to, conventional techniques, such as papain or pepsindigestion.

The present invention provides, in one particular aspect, isolatedPCSK9-specific antagonists which antagonize PCSK9 function. Inparticular embodiments, said PCSK9-specific antagonists inhibit PCSK9'santagonism of cellular LDL uptake. Disclosed PCSK9-specific antagonistseffectively antagonize PCSK9's inhibition of LDL uptake and thus, formdesirable molecules for lowering plasma LDL-cholesterol levels; see,e.g., Cohen et al., 2005 Nat. Genet. 37:161-165 (wherein significantlylower plasma LDL cholesterol levels were noted in individualsheterozygous for a nonsense mutation in allele PCSK9); Rashid et al.,2005 Proc. Natl. Acad. Sci. USA 102:5374-5379 (wherein PCSK9-knockoutmice evidenced increased numbers of LDLRs in hepatocytes, acceleratedplasma LDL clearance, and significantly lower plasma cholesterollevels); and Cohen et al., 2006 N. Engl. J. Med. 354:1264-1272 (whereinhumans heterozygous for mutated, loss of function, PCSK9 exhibited asignificant reduction in the long-term risk of developingatherosclerotic heart disease).

Through repeat experiments, five PCSK9-specific antagonists, namelyantibody molecules 1CX1G08, 3BX5C01, 3CX2A06, 3CX3D02, and 3CX4B08dose-dependently inhibited the effects of PCSK9 on LDL uptake. Inspecific embodiments, the present invention, thus, encompassesPCSK9-specific antagonists and, in more specific embodiments, antibodymolecules comprising the heavy and/or light chain variable regionscontained within these antibody molecules, as well as equivalents(characterized as having one or more conservative amino acidsubstitutions) or homologs thereof. Particular embodiments compriseisolated PCSK9-specific antagonists that comprise the CDR domainsdisclosed herein or sets of heavy and/or light chain CDR domainsdisclosed herein, or equivalents thereof, characterized as having one ormore conservative amino acid substitutions. Use of the terms “domain” or“region” herein simply refers to the respective portion of the antibodymolecule wherein the sequence or segment at issue will reside or, in thealternative, currently resides.

In specific embodiments, the present invention provides isolatedPCSK9-specific antagonists and, in more specific embodiments, antibodymolecules comprising a heavy chain variable region selected from thegroup consisting of: SEQ ID NO: 11, SEQ ID NO: 27, SEQ ID NO: 45, SEQ IDNO: 61 and SEQ ID NO: 79, equivalents thereof characterized as havingone or more conservative amino acid substitutions, and homologs thereof.The disclosed antagonists should inhibit PCSK9-dependent inhibition ofcellular LDL uptake. In specific embodiments, the present inventionprovides homologs of the disclosed antagonists characterized as being atleast 90% homologous to antagonists disclosed herein; said antagonistswhich inhibit PCSK9-dependent inhibition of cellular LDL uptake.

In specific embodiments, the present invention provides isolatedPCSK9-specific antagonists and, in more specific embodiments, antibodymolecules comprising a light chain variable region selected from thegroup consisting of: SEQ ID NO: 93, SEQ ID NO: 95, SEQ ID NO: 97, SEQ IDNO: 99 and SEQ ID NO: 101; equivalents thereof characterized as havingone or more conservative amino acid substitutions, and homologs thereof.The disclosed antagonists should inhibit PCSK9-dependent inhibition ofcellular LDL uptake. In specific embodiments, the present inventionprovides homologs of the disclosed antagonists characterized as being atleast 90% homologous to antagonists disclosed herein; said antagonistswhich inhibit PCSK9-dependent inhibition of cellular LDL uptake.

In specific embodiments, the present invention provides isolatedPCSK9-specific antagonists and, in more specific embodiments, antibodymolecules which comprise: (i) a heavy chain variable region comprisingSEQ ID NO: 11 and a light chain variable region comprising SEQ ID NO:93, (ii) a heavy chain variable region comprising SEQ ID NO: 27 and alight chain variable region comprising SEQ ID NO: 95, (iii) a heavychain variable region comprising SEQ ID NO: 45 and a light chainvariable region comprising SEQ ID NO: 97, (iv) a heavy chain variableregion comprising SEQ ID NO: 61 and a light chain variable regioncomprising SEQ ID NO: 99, (v) a heavy chain variable region comprisingSEQ ID NO: 79 and a light chain variable region comprising SEQ ID NO:101; or equivalent of any of the foregoing antibody moleculescharacterized as having one or more conservative amino acidsubstitutions in the prescribed sequences. Specific embodiments are saidantagonists which inhibit PCSK9-dependent inhibition of cellular LDLuptake.

In particular embodiments, the present invention provides isolatedPCSK9-specific antagonists and, in more specific embodiments, PCSK9antibody molecules that comprise variable heavy CDR3 sequence selectedfrom the group consisting of: SEQ ID NO: 17, SEQ ID NO: 33, SEQ ID NO:51, SEQ ID NO: 67 and SEQ ID NO: 85; and conservative modificationsthereof; specific embodiments of which inhibit PCSK9-dependentinhibition of cellular LDL uptake. Specific embodiments provide isolatedantagonists which comprise a heavy chain variable region wherein CDR1,CDR2, and/or CDR3 sequences comprise (i) SEQ ID NO: 13, SEQ ID NO: 15and/or SEQ ID NO: 17, respectively, (ii) SEQ ID NO: 29, SEQ ID NO: 31and/or SEQ ID NO: 33, respectively, (iii) SEQ ID NO: 47, SEQ ID NO: 49and/or SEQ ID NO: 51, respectively, (iv) SEQ ID NO: 63, SEQ ID NO: 65and/or SEQ ID NO: 67, respectively, (v) SEQ NO: 81, SEQ ID NO: 83 and/orSEQ ID NO: 85, respectively; or equivalents thereof characterized ashaving one or more conservative amino acid substitutions in any one ormore of the CDR sequences.

In particular embodiments, the present invention provides isolatedPCSK9-specific antagonists and, in more specific embodiments, antibodymolecules which comprise variable light CDR3 sequence selected from thegroup consisting of: SEQ ID NO: 7, SEQ ID NO: 23, SEQ ID NO: 41, SEQ IDNO: 57 and SEQ ID NO: 75; and conservative modifications thereof;specific embodiments of which inhibit PCSK9-dependent inhibition ofcellular LDL uptake. Specific embodiments provide isolated antagonistswhich comprise a light chain variable region wherein CDR1, CDR2, and/orCDR3 sequences comprise (i) SEQ ID NO: 3, SEQ ID NO: 5, and/or SEQ IDNO: 7, respectively, (ii) SEQ ID NO: 21, SEQ ID NO: 5 and/or SEQ ID NO:23, respectively, (iii) SEQ ID NO: 37, SEQ ID NO: 39 and/or SEQ ID NO:41, respectively, (iv) SEQ ID NO: 55, SEQ ID NO: 39 and/or SEQ ID NO:57, respectively, (v) SEQ ID NO: 71, SEQ ID NO: 73 and/or SEQ ID NO: 75,respectively; or an equivalent thereof characterized as having one ormore conservative amino acid substitutions in any one or more of the CDRsequences.

In particular embodiments, the present invention provides isolatedPCSK9-specific antagonists and, in more specific embodiments, antibodymolecules which comprise heavy chain variable region CDR3 sequence andlight chain variable region CDR3 sequence comprising (i) SEQ ID NOs: 17and 7, respectively, (ii) SEQ ID NOs: 33 and 23, respectively, (iii) SEQID NOs: 51 and 41, respectively, (iv) SEQ ID NOs: 67 and 57,respectively, and (v) SEQ ID NOs: 85 and 75, respectively; orconservative modifications thereof in any one or more of the CDR3sequences; specific embodiments of which inhibit PCSK9-dependentinhibition of cellular LDL uptake.

Specific embodiments provide isolated PCSK9-specific antagonists and, inmore specific embodiments, antibody molecules which comprise heavy chainvariable region CDR1, CDR2, and CDR3 sequences and light chain variableregion CDR1, CDR2, and CDR3 sequences comprising (i) SEQ ID NOs: 13, 15,17, 3, 5 and 7, respectively, (ii) SEQ ID NOs: 29, 31, 33, 21, 5 and 23,respectively, (iii) SEQ ID NOs: 47, 49, 51, 37, 39 and 41, respectively,(iv) SEQ ID NOs: 63, 65, 67, 55, 39 and 57, respectively, and (v) SEQ IDNOs: 81, 83, 85, 71, 73 and 75, respectively; and equivalents thereofcharacterized as having one or more conservative amino acidsubstitutions in any one or more of the CDR sequences; specificembodiments of which inhibit PCSK9-dependent inhibition of cellular LDLuptake.

Conservative amino acid substitutions, as one of ordinary skill in theart will appreciate, are substitutions that replace an amino acidresidue with one imparting similar or better (for the intended purpose)functional and/or chemical characteristics. For example, conservativeamino acid substitutions are often ones in which the amino acid residueis replaced with an amino acid residue having a similar side chain.Families of amino acid residues having similar side chains have beendefined in the art. These families include amino acids with basic sidechains (e.g., lysine, arginine, histidine), acidic side chains (e.g.,aspartic acid, glutamic acid), uncharged polar side chains (e.g.,glycine, asparagine, glutamine, serine, threonine, tyrosine, cysteine,tryptophan), nonpolar side chains (e.g., alanine, valine, leucine,isoleucine, proline, phenylalanine, methionine), beta-branched sidechains (e.g., threonine, valine, isoleucine) and aromatic side chains(e.g., tyrosine, phenylalanine, tryptophan, histidine). Suchmodifications are not designed to significantly reduce or alter thebinding or functional inhibition characteristics of the PCSK9-specificantagonist, albeit they may improve such properties. The purpose formaking a substitution is not significant and can include, but is by nomeans limited to, replacing a residue with one better able to maintainor enhance the structure of the molecule, the charge or hydrophobicityof the molecule, or the size of the molecule. For instance, one maydesire simply to substitute a less desired residue with one of the samepolarity or charge. Such modifications can be introduced by standardtechniques known in the art, such as site-directed mutagenesis andPCR-mediated mutagenesis. One specific means by which those of skill inthe art accomplish conservative amino acid substitutions is alaninescanning mutagenesis as discussed in, for example, MacLennan et al.,1998 Acta Physiol. Scand. Suppl. 643:55-67, and Sasaki et al., 1998 Adv.Biophys. 35:1-24. The altered antagonists are then tested for retainedor better function using functional assays available in the art ordescribed herein. PCSK9-specific antagonists possessing one or more suchconservative amino acid substitutions which retain the ability toselectively bind to human PCSK9 and antagonize PCSK9 functioning at alevel the same or better than the molecule not possessing such aminoacid alterations are referred to herein as “functional equivalents” ofthe disclosed antagonists and form specific embodiments of the presentinvention.

In another aspect, the present invention provides isolatedPCSK9-specific antagonists and, in more specific embodiments, antibodymolecules which comprise heavy and/or light chain variable regionscomprising amino acid sequences that are homologous to the correspondingamino acid sequences of the disclosed antibodies, wherein the antibodymolecules inhibit PCSK9-dependent inhibition of cellular LDL uptake.Specific embodiments are antagonists which comprise heavy and/or lightchain variable regions which are at least 90% homologous to disclosedheavy and/or light chain variable regions, respectively. Reference to“at least 90% homologous” includes at least 90, 91, 92, 93, 94, 95, 96,97, 98, 99 and 100% homologous sequences.

PCSK9-specific antagonists with amino acid sequences homologous to theamino acid sequences of antagonists described herein are typicallyproduced to improve one or more of the properties of the antagonistwithout changing its specificity for PCSK9. One method of obtaining suchsequences, which is not the only method available to the skilledartisan, is to mutate sequence encoding the PCSK9-specific antagonist orspecificity-determining region(s) thereof, express an antagonistcomprising the mutated sequence(s), and test the encoded antagonist forretained function using available functional assays including thosedescribed herein. Mutation may be by site-directed or randommutagenesis. As one of skill in the art will appreciate, however, othermethods of mutagenesis can readily bring about the same effect. Forexample, in certain methods, the spectrum of mutants are constrained bynon-randomly targeting conservative substitutions based on either aminoacid chemical or structural characteristics, or else by proteinstructural considerations. In affinity maturation experiments, severalsuch mutations may be found in a single selected molecule, whether theyare randomly or non-randomly selected. There are also variousstructure-based approaches toward affinity maturation as demonstratedin, e.g., U.S. Pat. No. 7,117,096, PCT Pub. Nos.: WO 02/084277 and WO03/099999.

As used herein, the percent homology between two amino acid sequences isequivalent to the percent identity between the two sequences. Thepercent identity between the two sequences is a function of the numberof identical positions shared by the sequences (i.e., % homology=# ofidentical positions/total # of positions×100), taking into account thenumber of gaps, and length of each gap, which need to be introduced foroptimal alignment of the two sequences. The comparison of sequences anddetermination of percent identity between sequences can be determinedusing methods generally known to those in the art and can beaccomplished using a mathematical algorithm. For example, the percentidentity between amino acid sequences and/or nucleotide sequences can bedetermined using the algorithm of Meyers and Miller, 1988 Comput. Appl.Biosci. 4:11-17, which has been incorporated into the ALIGN program(version 2.0). In addition, the percent identity between amino acidsequences or nucleotide sequences can be determined using the GAPprogram in the GCG software package available online from Accelrys,using its default parameters.

In one aspect, the present invention provides isolated PCSK9-specificantibody molecules for human PCSK9 which have therein at least one lightchain variable domain and at least one heavy chain variable domain (VLand VH, respectively).

Manipulation of protein-specific molecules to produce other bindingmolecules with similar or better specificity is well within the realm ofone skilled in the art. This can be accomplished, for example, usingtechniques of recombinant DNA technology. One specific example of thisinvolves the introduction of DNA encoding the immunoglobulin variableregion, or one or more of the CDRs, of an antibody to the variableregion, constant region, or constant region plus framework regions, asappropriate, of a different immunoglobulin. Such molecules formimportant aspects of the present invention. Specific immunoglobulins,into which particular disclosed sequences may be inserted or, in thealternative, form the essential part of, include but are not limited tothe following antibody molecules which form particular embodiments ofthe present invention: a Fab (monovalent fragment with variable light(VL), variable heavy (VH), constant light (CL) and constant heavy 1(CH1) domains), a F(ab′)₂ (bivalent fragment comprising two Fabfragments linked by a disulfide bridge or alternative at the hingeregion), a Fd (VH and CH1 domains), a Fv (VL and VH domains), a scFv (asingle chain Fv where VL and VH are joined by a linker, e.g., a peptidelinker, see, e.g., Bird et al., 1988 Science 242:423-426, Huston et al.,1988 PNAS USA 85:5879-5883), a bispecific antibody molecule (an antibodymolecule comprising a PCSK9-specific antibody or antigen bindingfragment as disclosed herein linked to a second functional moiety havinga different binding specificity than the antibody, including, withoutlimitation, another peptide or protein such as an antibody, or receptorligand), a bispecific single chain Fv dimer (see, e.g., PCT/US92/09965),an isolated CDR3, a minibody (single chain-CH3 fusion that selfassembles into a bivalent dimer of about 80 kDa), a ‘scAb’ (an antibodyfragment containing VH and VL as well as either CL or CH1), a dAbfragment (VH domain, see, e.g., Ward et al., 1989 Nature 341:544-546,and McCafferty et al., 1990 Nature 348:552-554; or VL domain; Holt etal., 2003 Trends in Biotechnology 21:484-489), a diabody (see, e.g.,Holliger et al., 1993 PNAS USA 90:6444-6448 and InternationalApplication Number WO 94/13804), a triabody, a tetrabody, a minibody (ascFv joined to a CH3; see, e.g., Hu et al., 1996 Cancer Res.56:3055-3061), IgG, IgG1, IgG2, IgG3, IgG4, IgM, IgD, IgA, IgE or anyderivatives thereof, and artificial antibodies based upon proteinscaffolds, including but not limited to fibronectin type III polypeptideantibodies (see, e.g. U.S. Pat. No. 6,703,199 and InternationalApplication Number WO 02/32925) or cytochrome B; see, e.g., Koide etal., 1998 J. Molec. Biol. 284:1141-1151, and Nygren et al., 1997 CurrentOpinion in Structural Biology 7:463-469. Certain antibody moleculesincluding, but not limited to, Fv, scFv, diabody molecules or domainantibodies (Domantis) may be stabilized by incorporating disulfidebridges to line the VH and VL domains, see, e.g., Reiter et al., 1996Nature Biotech. 14:1239-1245. Bispecific antibodies may be producedusing conventional technologies (see, e.g., Holliger & Winter, 1993Current Opinion Biotechnol. 4:446-449, specific methods of which includeproduction chemically, or from hybrid hybridomas) and other technologiesincluding, but not limited to, the BiTE™ technology (moleculespossessing antigen binding regions of different specificity with apeptide linker) and knobs-into-holes engineering (see, e.g., Ridgeway etal., 1996 Protein Eng. 9:616-621). Bispecific diabodies may be producedin E. coli, and these molecules as other PCSK9-specific antagonists, asone of skill in the art will appreciate, may be selected using phagedisplay in the appropriate libraries (see, e.g., InternationalApplication Number WO 94/13804).

Variable domains, into which CDRs of interest are inserted, may beobtained from any germ-line or rearranged human variable domain.Variable domains may also be synthetically produced. The CDR regions canbe introduced into the respective variable domains using recombinant DNAtechnology. One means by which this can be achieved is described inMarks et al., 1992 Bio/Technology 10:779-783. A variable heavy domainmay be paired with a variable light domain to provide an antigen bindingsite. In addition, independent regions (e.g., a variable heavy domainalone) may be used to bind antigen. The artisan is well aware, as well,that two domains of an Fv fragment, VL and VH, while perhaps coded byseparate genes, may be joined, using recombinant methods, by a syntheticlinker that enables them to be made as a single protein chain in whichthe VL and VH regions pair to form monovalent molecules (scFvs).

Specific embodiments provide the CDR(s) in germline framework regions.Specific embodiments herein provide heavy chain CDR(s) selected from thegroup consisting of SEQ ID NO: 17 and SEQ ID NO: 85 into VH3 in place ofthe relevant CDR(s). Specific embodiments herein provide heavy chainCDR(s) selected from the group consisting of: SEQ ID NO: 33, SEQ ID NO:51 and SEQ ID NO: 67 into VH5 in place of the relevant CDR(s). Specificembodiments herein provide light chain CDR(s) selected from the groupconsisting of SEQ ID NO: 7, SEQ ID NO: 23 and SEQ ID NO: 75 into VL3 inplace of the relevant CDR(s). Specific embodiments herein provide lightchain CDR(s) selected from the group consisting of SEQ ID NO: 41 and SEQID NO: 57 into VK1 in place of the relevant CDR(s).

Specific embodiments provide antibody molecules as defined herein whichcomprise a light chain region comprising sequence selected from thegroup consisting of: SEQ ID NO: 1, SEQ ID NO: 19, SEQ ID NO: 35, SEQ IDNO: 53 and SEQ ID NO: 69. Additional embodiments provide antibodymolecules which comprise both alight chain region as described and aheavy chain region comprising sequence selected from the groupconsisting of SEQ ID NO: 9, SEQ ID NO: 25, SEQ ID NO: 43, SEQ ID NO: 59and SEQ ID NO: 77.

The present invention encompasses antibody molecules that are human,humanized, deimmunized, chimeric and primatized. The invention alsoencompasses antibody molecules produced by the process of veneering;see, e.g., Mark et al., 1994 Handbook of Experimental Pharmacology, vol.113: The pharmacology of monoclonal Antibodies, Springer-Verlag, pp.105-134. “Human” in reference to the disclosed antibody moleculesspecifically refers to antibody molecules having variable and/orconstant regions derived from human germline immunoglobulin sequences,wherein said sequences may, but need not, be modified/altered to havecertain amino acid substitutions or residues that are not encoded byhuman germline immunoglobulin sequence. Such mutations can be introducedby methods including, but not limited to, random or site-specificmutagenesis in vitro, or by somatic mutation in vivo. Specific examplesof mutation techniques discussed in the literature are that disclosed inGram et al., 1992 PNAS USA 89:3576-3580; Barbas et al., 1994 PNAS USA91:3809-3813, and Schier et al., 1996 J. Mol. Biol. 263:551-567. Theseare only specific examples and do not represent the only availabletechniques. There are a plethora of mutation techniques in thescientific literature which are available to, and widely appreciated by,the skilled artisan. “Humanized” in reference to the disclosed antibodymolecules refers specifically to antibody molecules wherein CDRsequences derived from another mammalian species, such as a mouse, aregrafted onto human framework sequences. “Primatized” in reference to thedisclosed antibody molecules refers to antibody molecules wherein CDRsequences of a non-primate are inserted into primate frameworksequences, see, e.g., WO 93/02108 and WO 99/55369.

Specific antibodies of the present invention are monoclonal antibodiesand, in particular embodiments, are in one of the following antibodyformats: IgD, IgA, IgE, IgM, IgG1, IgG2, IgG3, IgG4 or any derivative ofany of the foregoing. The language “derivatives thereof” or“derivatives” in this respect includes, inter alia, (i) antibodies andantibody molecules with modifications in one or both variable regions(i.e., VH and/or VL), (ii) antibodies and antibody molecules withmanipulations in the constant regions of VH and/or VL, and (iii)antibodies and antibody molecules that contain additional chemicalmoieties which are not normally a part of the immunoglobulin molecule(e.g., pegylation).

Manipulations of the variable regions can be within one or more of theVH and/or VL CDR regions. Site-directed mutagenesis, random mutagenesisor other method for generating sequence or molecule diversity can beutilized to create mutants which can subsequently be tested for aparticular functional property of interest in available in vitro or invivo assays including those described herein.

Antibodies of the present invention also include those in whichmodifications have been made to the framework residues within VH and/orVL to improve one or more properties of the antibody of interest.Typically, such framework modifications are made to decrease theimmunogenicity of the antibody. For example, one approach is to“backmutate” one or more framework residues to the correspondinggermline sequence. More specifically, an antibody that has undergonesomatic mutation may contain framework residues that differ from thegermline sequence from which the antibody is derived. Such residues canbe identified by comparing the antibody framework sequences to thegermline sequences from which the antibody is derived. Such“backmutated” antibodies are also intended to be encompassed by theinvention. Another type of framework modification involves mutating oneor more residues within the framework region, or even within one or moreCDR regions, to remove T cell epitopes to thereby reduce the potentialimmunogenicity of the antibody. This approach is also referred to as“deimmunization” and is described in further detail in U.S. PatentPublication No. 20030153043 by Carr et al.

In addition or alternative to modifications made within the framework orCDR regions, antibodies of the invention may be engineered to includemodifications within the Fc region, where present, typically to alterone or more functional properties of the antibody, such as serumhalf-life, complement fixation, Fc receptor binding, and/orantigen-dependent cellular cytotoxicity.

The concept of generating “hybrids” or “combinatorial” IgG formscomprising various antibody isotypes to hone in on desired effectorfunctionality has generally been described; see, e.g., Tao et al., 1991J. Exp. Med. 173:1025-1028. A specific embodiment of the presentinvention encompasses antibody molecules that possess specificmanipulations in the Fc region which have been found to result inreduced binding to FcγR receptors or C1q on the part of the antibody.The present invention, therefore, encompasses antibodies in accordancewith the present description that do not provoke (or provoke to a lesserextent) antibody-dependent cellular cytotoxicity (“ADCC”),complement-mediated cytotoxicity (“CMC”), or form immune complexes,while retaining normal pharmacokinetic (“PK”) properties. Specificembodiments of the present invention provide an antibody molecule asdefined in accordance with the present invention which comprises, aspart of its immunoglobulin structure, SEQ ID NO: 87. FIG. 6 illustratesa comparison of sequence comprising SEQ ID NO: 87, particularly IgG2m4,with IgG1, IgG2, and IgG4.

Specific PCSK9-specific antagonists may carry a detectable label, or maybe conjugated to a toxin (e.g., a cytotoxin), a radioactive isotope, aradionuclide, a liposome, a targeting moiety, a biosensor, a cationictail, or an enzyme (e.g., via a peptidyl bond or linker). SuchPCSK9-specific antagonist compositions form an additional aspect of thepresent invention.

In another aspect, the present invention provides isolated nucleic acidencoding disclosed PCSK9-specific antagonists. The nucleic acid may bepresent in whole cells, in a cell lysate, or in a partially purified orsubstantially pure form. A nucleic acid is “isolated” or “renderedsubstantially pure” when purified away from other cellular components orother contaminants, e.g., other cellular nucleic acids or proteins, forexample, using standard techniques, including without limitation,alkaline/SDS treatment, CsCl banding, column chromatography, agarose gelelectrophoresis and other suitable methods known in the art. The nucleicacid may include DNA (inclusive of cDNA) and/or RNA. Nucleic acids ofthe present invention can be obtained using standard molecular biologytechniques. For antibodies expressed by hybridomas (e.g., hybridomasprepared from transgenic mice carrying human immunoglobulin genes),cDNAs encoding the light and heavy chains of the antibody made by thehybridoma can be obtained by standard PCR amplification or cDNA cloningtechniques. For antibodies obtained from an immunoglobulin gene library(e.g., using phage display techniques), nucleic acid encoding theantibody can be recovered from the library.

The present invention encompasses isolated nucleic acid encodingdisclosed variable heavy and/or light chains and select componentsthereof, particularly the disclosed respective CDR3 regions. In specificembodiments hereof, the CDR(s) are provided within antibody frameworkregions. Specific embodiments provide isolated nucleic acid encoding theCDR(s) into germline framework regions. Specific embodiments hereinprovide isolated nucleic acid encoding heavy chain CDR(s) SEQ ID NOs: 18or 86 into VH3 in place of the nucleic acid encoding the relevantCDR(s). Specific embodiments herein provide isolated nucleic acidencoding heavy chain CDR(s) SEQ ID NOs: 34, 52 or 68 into VH5 in placeof the nucleic acid encoding the relevant CDR(s). Specific embodimentsherein provide isolated nucleic encoding light chain CDR(s) SEQ ID NOs:8, 24, or 76 into VL3 in place of the nucleic acid encoding the relevantCDR(s). Specific embodiments herein provide isolated nucleic encodinglight chain CDR(s) SEQ ID NOs: 42 or 58 into VK1 in place of the nucleicacid encoding the relevant CDR(s). The isolated nucleic acid encodingthe variable regions can be provided within any desired antibodymolecule format including, but not limited to, the following: F(ab′)₂, aFab, a Fv, a scFv, bispecific antibody molecules (antibody moleculescomprising a PCSK9-specific antibody or antigen binding fragment asdisclosed herein linked to a second functional moiety having a differentbinding specificity than the antibody, including, without limitation,another peptide or protein such as an antibody, or receptor ligand), abispecific single chain Fv dimer, a minibody, a dAb fragment, diabody,triabody or tetrabody, a minibody, IgG, IgG1, IgG2, IgG3, IgG4, IgM,IgD, IgA, IgE or any derivatives thereof.

Specific embodiments provide isolated nucleic acid which encodesantibody molecules as defined herein which comprise a light chain regioncomprising sequence selected from the group consisting of: SEQ ID NO: 1,SEQ ID NO: 19, SEQ ID NO: 35, SEQ NO: 53 and SEQ ID NO: 69. Particularembodiments comprise nucleic acid selected from the group consisting of:SEQ ID NO: 2, SEQ ID NO: 20, SEQ ID NO: 36, SEQ ID NO: 54 and SEQ ID NO:70: Additional embodiments provide antibody molecules which compriseboth a light chain region as described and a heavy chain regioncomprising sequence selected from the group consisting of: SEQ ID NO: 9,SEQ ID NO: 25, SEQ ID NO: 43, SEQ ID NO: 59 and SEQ ID NO: 77. Thenucleic acid sequence encoding the heavy chain region may in specificembodiments comprise sequence selected from the group consisting of: SEQID NO: 10, SEQ ID NO: 26, SEQ ID NO: 44, SEQ ID NO: 60 and SEQ ID NO:78.

Specific embodiments provide isolated nucleic acid which encodesantibody molecules comprising a heavy chain variable domain selectedfrom the group consisting of: SEQ ID NO: 11, SEQ ID NO: 27, SEQ ID NO:45, SEQ ID NO: 61 and SEQ ID NO: 79; specific embodiments of whichcomprise nucleic acid sequence SEQ ID NO: 12, SEQ ID NO: 28, SEQ ID NO:46, SEQ ID NO: 62 or SEQ ID NO: 80, respectively. Specific embodimentsof the present invention provide isolated nucleic acid encoding antibodymolecules, which comprises: (i) heavy chain CDR1 nucleotide sequence SEQID NO: 14, (ii) heavy chain CDR2 nucleotide sequence SEQ ID NO: 16,and/or (iii) heavy chain CDR3 nucleotide sequence SEQ ID NO: 18.Specific embodiments of the present invention provide isolated nucleicacid encoding antibody molecules, which comprises: (i) heavy chain CDR1nucleotide sequence SEQ ID NO: 30, (ii) heavy chain CDR2 nucleotidesequence SEQ ID NO: 32, and/or (iii) heavy chain CDR3 nucleotidesequence SEQ ID NO: 34. Specific embodiments of the present inventionprovide isolated nucleic acid encoding antibody molecules, whichcomprises: (i) heavy chain CDR1 nucleotide sequence SEQ ID NO: 48, (ii)heavy chain CDR2 nucleotide sequence SEQ ID NO: 50, and/or (iii) heavychain CDR3 nucleotide sequence SEQ ID NO: 52. Specific embodiments ofthe present invention provide isolated nucleic acid encoding antibodymolecules, which comprises: (i) heavy chain CDR1 nucleotide sequence SEQID NO: 64, (ii) heavy chain CDR2 nucleotide sequence SEQ ID NO: 66,and/or (iii) heavy chain CDR3 nucleotide sequence SEQ ID NO: 68.Specific embodiments of the present invention provide isolated nucleicacid encoding antibody molecules, which comprises: (i) heavy chain CDR1nucleotide sequence SEQ ID NO: 82, (ii) heavy chain CDR2 nucleotidesequence SEQ ID NO: 84, and/or (iii) heavy chain CDR3 nucleotidesequence SEQ ID NO: 86. Specific embodiments provide isolated nucleicacid encoding antibody molecules comprising a light chain variabledomain selected from the group consisting of: SEQ ID NO: 93, SEQ ID NO:95, SEQ ID NO: 97, SEQ ID NO: 99 and SEQ ID NO: 101; specificembodiments of which comprise nucleic acid sequence SEQ ID NO: 94, SEQID NO: 96, SEQ ID NO: 98, SEQ ID NO: 100, or SEQ ID NO: 102,respectively. Specific embodiments of the present invention provideisolated nucleic acid encoding antibody molecules, which comprises: (i)light chain CDR1 nucleotide sequence SEQ ID NO: 4, (ii) light chain CDR2nucleotide sequence SEQ ID NO: 6, and/or (iii) light chain CDR3nucleotide sequence SEQ ID NO: 8. Specific embodiments of the presentinvention provide isolated nucleic acid encoding antibody molecules,which comprises: (i) light chain CDR1 nucleotide sequence SEQ ID NO: 22,(ii) light chain CDR2 nucleotide sequence SEQ ID NO: 6, and/or (iii)light chain CDR3 nucleotide sequence SEQ ID NO: 24. Specific embodimentsof the present invention provide isolated nucleic acid encoding antibodymolecules, which comprises: (i) light chain CDR1 nucleotide sequence SEQID NO: 38, (ii) light chain CDR2 nucleotide sequence SEQ ID NO: 40,and/or (iii) light chain CDR3 nucleotide sequence SEQ ID NO: 42.Specific embodiments of the present invention provide isolated nucleicacid encoding antibody molecules, which comprises: (i) light chain CDR1nucleotide sequence SEQ ID NO: 56, (ii) light chain CDR2 nucleotidesequence SEQ ID NO: 40, and/or (iii) light chain CDR3 nucleotidesequence SEQ ID NO: 58. Specific embodiments of the present inventionprovide isolated nucleic acid encoding antibody molecules, whichcomprises: (i) light chain CDR1 nucleotide sequence SEQ ID NO: 72, (ii)light chain CDR2 nucleotide sequence SEQ ID NO: 74, and/or (iii) lightchain CDR3 nucleotide sequence SEQ ID NO: 76. Specific embodiments ofthe present invention encompass nucleic acid encoding antibody moleculesthat possess manipulations in the Fc region which result in reducedbinding to FcγR receptors or C1q on the part of the antibody. Onespecific embodiment of the present invention is isolated nucleic acidwhich comprises SEQ ID NO: 88. In specific embodiments, syntheticPCSK9-specific antagonists can be produced by expression from nucleicacid generated from oligonucleotides synthesized and assembled withinsuitable expression vectors; see, e.g., Knappick et al., 2000 J. Mol.Biol. 296:57-86, and Krebs et al., 2001 J. Immunol. Methods 254:67-84.

Also included within the present invention are isolated nucleic acidscomprising nucleotide sequences which are at least about 90% identicaland more preferably at least about 95% identical to nucleotide sequencesdescribed herein, and which nucleotide sequences encode PCSK9-specificantagonists which inhibit PCSK9-dependent inhibition of cellular LDLuptake. Sequence comparison methods to determine identity are known tothose skilled in the art and include those discussed earlier. Referenceto “at least about 90% identical” includes at least about 90, 91, 92,93, 94, 95, 96, 97, 98, 99 or 100% identical.

The invention further provides isolated nucleic acid which hybridizes tothe complement of nucleic acid disclosed herein under particularhybridization conditions, which nucleic acid binds specifically to PCSK9and antagonizes PCSK9 function. Methods for hybridizing nucleic acidsare well-known in the art; see, e.g., Ausubel, Current Protocols inMolecular Biology, John Wiley & Sons, N.Y., 6.3.1-6.3.6, 1989. Asdefined herein, moderately stringent hybridization conditions may use aprewashing solution containing 5× sodium chloride/sodium citrate (SSC),0.5% w/v SDS, 1.0 mM EDTA (pH 8.0), hybridization buffer of about 50%v/v formamide, 6×SSC, and a hybridization temperature of 55° C. (orother similar hybridization solutions, such as one containing about 50%v/v formamide, with a hybridization temperature of 42° C.), and washingconditions of 60° C., in 0.5×SSC, 0.1% w/v SDS. A stringenthybridization condition may be at 6×SSC at 45° C., followed by one ormore washes in 0.1×SSC, 0.2% SDS at 68° C. Furthermore, one of skill inthe art can manipulate the hybridization and/or washing conditions toincrease or decrease the stringency of hybridization such that nucleicacids comprising nucleotide sequences that are at least 65, 70, 75, 80,85, 90, 95, 98, or 99% identical to each other typically remainhybridized to each other. The basic parameters affecting the choice ofhybridization conditions and guidance for devising suitable conditionsare set forth by Sambrook et al., Molecular Cloning: A LaboratoryManual, Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y.,chapters 9 and 11, 1989 and Ausubel et al. (eds), Current Protocols inMolecular Biology, John Wiley & Sons, Inc., sections 2.10 and 6.3-6.4,1995, and can be readily determined by those having ordinary skill inthe art based on, for example, the length and/or base composition of theDNA.

In another aspect, the present invention provides vectors comprisingsaid nucleic acid. Vectors in accordance with the present inventioninclude, but are not limited to, plasmids and other expressionconstructs (e.g., phage or phagemid, as appropriate) suitable for theexpression of the desired antibody molecule at the appropriate level forthe intended purpose; see, e.g., Sambrook & Russell, Molecular Cloning:A Laboratory Manual: 3^(rd) Edition, Cold Spring Harbor LaboratoryPress. For most cloning purposes, DNA vectors may be used. Typicalvectors include plasmids, modified viruses, bacteriophage, cosmids,yeast artificial chromosomes, and other forms of episomal or integratedDNA. It is well within the purview of the skilled artisan to determinean appropriate vector for a particular gene transfer, generation of arecombinant PCSK9-specific antagonist, or other use. In specificembodiments, in addition to a recombinant gene, the vector may alsocontain an origin of replication for autonomous replication in a hostcell, appropriate regulatory sequences, such as a promoter, atermination sequence, a polyadenylation sequence, an enhancer sequence,a selectable marker, a limited number of useful restriction enzymesites, other sequences as appropriate and the potential for high copynumber. Examples of expression vectors for the production ofprotein-specific antagonists are well known in the art; see, e.g.,Persic et al., 1997 Gene 187:9-18; Boel et al., 2000J. Immunol. Methods239:153-166, and Liang et al., 2001 J. Immunol. Methods 247:119-130. Ifdesired, nucleic acid encoding the antagonist may be integrated into thehost chromosome using techniques well known in the art; see, e.g.,Ausubel, Current Protocols in Molecular Biology, John Wiley & Sons,1999, and Marks et al., International Application Number WO 95/17516.Nucleic acid may also be expressed on plasmids maintained episomally orincorporated into an artificial chromosome; see, e.g., Csonka et al.,2000 J. Cell Science 113:3207-3216; Vanderbyl et al., 2002 MolecularTherapy 5:10. Specifically with regards to antibody molecules, theantibody light chain gene and the antibody heavy chain gene can beinserted into separate vectors or, more typically, both genes may beinserted into the same expression vector. Nucleic acid encoding anyPCSK9-specific antagonist can be inserted into an expression vectorusing standard methods (e.g., ligation of complementary restrictionsites on the nucleic acid fragment and vector, or blunt end ligation ifno restriction sites are present). Another specific example of how thismay be carried out is through use of recombinational methods, e.g. theClontech “InFusion” system, or Invitrogen “TOPO” system (both in vitro),or intracellularly (e.g. the Cre-Lox system). Specifically with regardsto antibody molecules, the light and heavy chain variable regions can beused to create full-length antibody genes of any antibody isotype byinserting them into expression vectors already encoding heavy chainconstant and light chain constant regions of the desired isotype suchthat the VH segment is operatively linked to the CH segment(s) withinthe vector and the VL segment is operatively linked to the CL segmentwithin the vector. Additionally or alternatively, the recombinantexpression vector comprising nucleic acid encoding a PCSK9-specificantagonist can encode a signal peptide that facilitates secretion of theantagonist from a host cell. The nucleic acid can be cloned into thevector such that the nucleic acid encoding a signal peptide is linkedin-frame adjacent to the PCSK9-specific antagonist-encoding nucleicacid. The signal peptide may be an immunoglobulin or anon-immunoglobulin signal peptide. Any technique available to theskilled artisan may be employed to introduce the nucleic acid into thehost cell; see, e.g., Morrison, 1985 Science, 229:1202. Methods ofsubcloning nucleic acid molecules of interest into expression vectors,transforming or transfecting host cells containing the vectors, andmethods of making substantially pure protein comprising the steps ofintroducing the respective expression vector into a host cell, andcultivating the host cell under appropriate conditions are well known.The PCSK9-specific antagonist so produced may be harvested from the hostcells in conventional ways. Techniques suitable for the introduction ofnucleic acid into cells of interest will depend on the type of cellbeing used. General techniques include, but are not limited to, calciumphosphate transfection, DEAE-Dextran, electroporation, liposome-mediatedtransfection and transduction using viruses appropriate to the cell lineof interest (e.g., retrovirus, vaccinia, baculovirus, or bacteriophage).

In another aspect, the present invention provides isolated cell(s)comprising nucleic acid encoding disclosed PCSK9-specific antagonists. Avariety of different cell lines can be used for recombinant productionof PCSK9-specific antagonists, including but not limited to those fromprokaryotic organisms (e.g., E. coli, Bacillus, and Streptomyces) andfrom Eukaryotic (e.g., yeast, Baculovirus, and mammalian); see, e.g.,Breitling et al., Recombinant antibodies, John Wiley & Sons, Inc. andSpektrum Akademischer Verlag, 1999. Plant cells, including transgenicplants, and animal cells, including transgenic animals (other thanhumans), comprising the nucleic acid or antagonists disclosed herein arealso contemplated as part of the present invention. Suitable mammaliancell lines including, but not limited to, those derived from ChineseHamster Ovary (CHO cells, including but not limited to DHFR-CHO cells(described in Urlaub and Chasin, 1980 Proc. Natl. Acad. Sci. USA77:4216-4220) used, for example, with a DHFR selectable marker (e.g., asdescribed in Kaufman and Sharp, 1982 Mol. Biol. 159:601-621), NS0myeloma Cells (where a GS expression system as described in WO 87/04462,WO 89/01036, and EP 338,841 may be used), COS cells, SP2 cells, HeLacells, baby hamster kidney cells, YB2/0 rat myeloma cells, humanembryonic kidney cells, human embryonic retina cells, and otherscomprising the nucleic acid or antagonists disclosed herein formadditional embodiments of the present invention. Specific embodiments ofthe present invention may employ E. coli; see, e.g., Plückthun, 1991Bio/Technology 9:545-551, or yeast, such as Pichia, and recombinantderivatives thereof (see, e.g., Li et al., 2006 Nat. Biotechnol.24:210-215). Additional specific embodiments of the present inventionmay employ eukaryotic cells for the production of PCSK9-specificantagonists, see, Chadd & Chamow, 2001 Current Opinion in Biotechnology12:188-194, Andersen & Krummen, 2002 Current Opinion in Biotechnology13:117, Larrick & Thomas, 2001 Current Opinion in Biotechnology12:411-418. Specific embodiments of the present invention may employmammalian cells able to produce PCSK9-specific antagonists with properpost translational modifications. Post translational modificationsinclude, but are by no means limited to, disulfide bond formation andglycosylation. Another type of post translational modification is signalpeptide cleavage. Preferred embodiments herein have the appropriateglycosylation; see, e., Yoo et al., 2002 J. Immunol. Methods 261:1-20.Naturally occurring antibodies contain at least one N-linkedcarbohydrate attached to a heavy chain. Id. Different types of mammalianhost cells can be used to provide for efficient post-translationalmodifications. Examples of such host cells include Chinese Hamster Ovary(CHO), HeLa, C6, PC12, and myeloma cells; see, Yoo et al., 2002 J.Immunol. Methods 261:1-20, and Persic et al., 1997 Gene 187:9-18.

In another aspect, the present invention provides isolated cell(s)comprising a polypeptide of the present invention.

In another aspect, the present invention provides a method of making aPCSK9-specific antagonist of the present invention, which comprisesincubating a cell comprising nucleic acid encoding the PCSK9-specificantagonist, or a heavy and/or light chain of a desired PCSK9-specificantagonist (dictated by the desired antagonist) with specificity forhuman PCSK9 under conditions that allow the expression of thePCSK9-specific antagonist, or the expression and assembly of said heavyand/or light chains into a PCSK9-specific antagonist, and isolating saidPCSK9-specific antagonist from the cell. One example by which togenerate particular desired heavy and/or light chain sequence is tofirst amplify (and modify) the germline heavy and/or light chainvariable sequences using PCR. Germline sequence for human heavy and/orlight variable regions are readily available to the skilled artisan,see, e.g., the “Vbase” human germline sequence database, and Kabat, E.A. et al., 1991 Sequences of Proteins of Immunological Interest, FifthEdition, U.S. Department of Health and Human Services, NIH PublicationNo. 91-3242; Tomlinson, I. M. et al., 1992 “The Repertoire of HumanGermline VH Sequences Reveals about Fifty Groups of VH Segments withDifferent Hypervariable Loops” J. Mol. Biol. 227:776-798; and Cox, J. P.L. et al., 1994 “A Directory of Human Germ-line Vκ Segments Reveals aStrong Bias in their Usage” Eur. J. Immunol. 24:827-836. Mutagenesis ofgermline sequences may be carried out using standard methods, e.g.,PCR-mediated mutagenesis where the mutations are incorporated into PCRprimers, or site-directed mutagenesis. If full-length antibodies aredesired, sequence is available for the human heavy chain constant regiongenes; see, e.g., Kabat. E. A. et al., 1991 Sequences of Proteins ofImmunological Interest, Fifth Edition, U.S. Department of Health andHuman Services, NIH Publication No. 91-3242. Fragments containing theseregions may be obtained, for example, by standard PCR amplification.Alternatively, the skilled artisan can avail him/herself of vectorsalready encoding heavy and/or light chain constant regions.

Available techniques exist to recombinantly produce other antibodymolecules which retain the specificity of an original antibody. Aspecific example of this is where DNA encoding the immunoglobulinvariable region or the CDRs is introduced into the constant regions, orconstant regions and framework regions, of another antibody molecule;see, e.g., EP-184,187, GB 2188638, and EP-239400. Cloning and expressionof antibody molecules, including chimeric antibodies, are described inthe literature; see, e.g., EP 0120694 and EP 0125023.

Antibody molecules in accordance with the present invention may, in oneinstance, be raised and then screened for characteristics identifiedherein using known techniques. Basic techniques for the preparation ofmonoclonal antibodies are described in the literature, see, e.g., Kohlerand Milstein (1975, Nature 256:495-497). Fully human monoclonalantibodies can be produced by available methods. These methods include,but are by no means limited to, the use of genetically engineered mousestrains which possess an immune system whereby the mouse antibody geneshave been inactivated and in turn replaced with a repertoire offunctional human antibody genes, while leaving other components of themouse immune system unchanged. Such genetically engineered mice allowfor the natural in vivo immune response and affinity maturation processwhich results in high affinity, full human monoclonal antibodies. Thistechnology is well known in the art and is fully detailed in variouspublications, including but not limited to U.S. Pat. Nos. 5,545,806;5,569,825; 5,625,126; 5,633,425; 5,789,650; 5,877,397; 5,661,016;5,814,318; 5,874,299; 5,770,249 (assigned to GenPharm International andavailable through Medarex, under the umbrella of the “UltraMab HumanAntibody Development System”); as well as U.S. Pat. Nos. 5,939,598;6,075,181; 6,114,598; 6,150,584 and related family members (assigned toAbgenix, disclosing their XenoMouse® technology). See also reviews fromKellerman and Green, 2002 Curr. Opinion in Biotechnology 13:593-597, andKontermann & Stefan, 2001 Antibody Engineering, Springer LaboratoryManuals.

Alternatively, a library of PCSK9-specific antagonists in accordancewith the present invention may be brought into contact with PCSK9, andones able to demonstrate specific binding selected. Functional studiescan then be carried out to ensure proper functionality, i.e., inhibitionof PCSK9-dependent inhibition of cellular LDL uptake. There are varioustechniques available to the skilled artisan for the selection ofprotein-specific molecules from libraries using enrichment technologiesincluding, but not limited to, phage display (e.g., see technology fromCambridge Antibody Technology (“CAT”) disclosed in U.S. Pat. Nos.5,565,332; 5,733,743; 5,871,907; 5,872,215; 5,885,793; 5,962,255;6,140,471; 6,225,447; 6,291,650; 6,492,160; 6,521,404; 6,544,731;6,555,313; 6,582,915; 6,593,081, as well as other U.S. family membersand/or applications which rely on priority filing GB 9206318, filed May24, 1992; see also Vaughn et al., 1996, Nature Biotechnology14:309-314), ribosome display (see, e.g., Hanes and Pluckthün, 1997Proc. Natl. Acad. Sci. 94:4937-4942), bacterial display (see, e.g.,Georgiou, a al., 1997 Nature Biotechnology 15:29-34) and/or yeastdisplay (see, e.g., Kieke, et al., 1997 Protein Engineering10:1303-1310). A library, for example, can be displayed on the surfaceof bacteriophage particles, with the nucleic acid encoding thePCSK9-specific antagonist expressed and displayed on its surface.Nucleic acid may then be isolated from bacteriophage particlesexhibiting the desired level of activity and the nucleic acid used inthe development of desired antagonist. Phage display has been thoroughlydescribed in the literature; see, e.g., Kontermann & Stefan, supra, andInternational Application Number WO 92/01047. Specifically with regardto antibody molecules, individual heavy or light chain clones inaccordance with the present invention may also be used to screen forcomplementary heavy or light chains, respectively, capable ofinteraction therewith to form a molecule of the combined heavy and lightchains; see, e.g., International Application Number WO 92/01047. Anymethod of panning which is available to the skilled artisan may be usedto identify PCSK9-specific antagonists. Another specific method foraccomplishing this is to pan against the target antigen in solution,e.g. biotinylated, soluble PCSK9, and then capture the PCSK9-specificantagonist-phage complexes on streptavidin-coated magnetic beads, whichare then washed to remove nonspecifically-bound phage. The capturedphage can then be recovered from the beads in the same way they would berecovered from the surface of a plate, (e.g. DTT) as described herein.

PCSK9-specific antagonists may be purified by techniques available toone of skill in the art. Titers of the relevant antagonist preparation,ascites, hybridoma culture fluids, or relevant sample may be determinedby various serological or immunological assays which include, but arenot limited to, precipitation, passive agglutination, enzyme-linkedimmunosorbent antibody (“ELISA”) techniques and radioimmunoassay (“RIA”)techniques.

In another aspect, the present invention provides a method forantagonizing the activity of PCSK9, which comprises contacting a cell ortissue sample typically effected by PCSK9 (i.e., comprising LDLreceptors) with a PCSK9-specific antagonist disclosed herein underconditions that allow said antagonist to bind to PCSK9 when present andinhibit PCSK9's inhibition of cellular LDL uptake. Specific embodimentsof the present invention include such methods wherein the cell is ahuman cell. In another aspect, the present invention provides a methodfor antagonizing the activity of PCSK9 in a subject, which comprisesadministering to the subject a therapeutically effective amount of aPCSK9-specific antagonist of the present invention. Use of the term“antagonizing” refers to the act of opposing, counteracting,neutralizing or curtailing one or more functions of PCSK9. Inhibition orantagonism of one or more of associated PCSK9 functional properties canbe readily determined according to methodologies known to the art (see,e.g., Barak & Webb, 1981 J. Cell Biol. 90:595-604; Stephan & Yurachek,1993 J. Lipid Res. 34:325330; and McNamara et al., 2006 Clinica ChimicaActa 369:158-167) as well as those described herein. Inhibition orantagonism will effectuate a decrease in PCSK9 activity relative to thatseen in the absence of the antagonist or, for example, that seen when acontrol antagonist of irrelevant specificity is present. Preferably, aPCSK9-specific antagonist in accordance with the present inventionantagonizes PCSK9 functioning to the point that there is a decrease ofat least 10%, of the measured parameter, and more preferably, a decreaseof at least 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% and 95% of themeasured parameter. Such inhibition/antagonism of PCSK9 functioning isparticularly effective in those instances where its functioning iscontributing at least in part to a particular phenotype, disease,disorder or condition which is negatively impacting the subject. Alsocontemplated are methods of using the disclosed antagonists in themanufacture of a medicament for treatment of a PCSK9-associated disease,disorder or condition or, alternatively, a disease, disorder orcondition that could benefit from the effects of a PCSK9 antagonist.PCSK9-specific antagonists disclosed herein may be used in a method oftreatment or diagnosis of a particular individual (human or primate).The method of treatment can be prophylactic or therapeutic in nature. Inanother aspect, the present invention provides a pharmaceuticallyacceptable composition comprising a PCSK9-specific antagonist of theinvention and a pharmaceutically acceptable carrier, excipient, diluent,stabilizer, buffer, or alternative designed to facilitate administrationof the antagonist in the desired format and amount to the treatedindividual. Methods of treatment in accordance with the presentinvention comprise administering to an individual a therapeutically (orprophylactically) effective amount of a PCSK9-specific antagonist of thepresent invention. Use of the terms “therapeutically effective” or“prophylactically effective” in reference to an amount refers to theamount necessary at the intended dosage to achieve the desiredtherapeutic/prophylactic effect for the period of time desired. Thedesired effect may be, for example, amelioration of at least one symptomassociated with the treated condition. These amounts will vary, as theskilled artisan will appreciate, according to various factors, includingbut not limited to the disease state, age, sex and weight of theindividual, and the ability of the PCSK9-specific antagonist to elicitthe desired effect in the individual. The response may be documented byin vitro assay, in vivo non-human animal studies, and/or furthersupported from clinical trials. The antagonist-based pharmaceuticalcomposition of the present invention may be formulated by any number ofstrategies known in the art, see, e.g., McGoff and Scher, 2000 SolutionFormulation of Proteins/Peptides: In—McNally, E. J., ed. ProteinFormulation and Delivery. New York, N.Y.: Marcel Dekker; pp. 139-158;Akers & Defilippis, 2000, Peptides and Proteins as Parenteral Solutions.In—Pharmaceutical Formulation Development of Peptides and Proteins.Philadelphia, Pa.: Taylor and Francis; pp. 145-177; Akers et al., 2002,Pharm. Biotechnol. 14:47-127. A pharmaceutically acceptable compositionsuitable for patient administration will contain an effective amount ofthe PCSK9-specific antagonist in a formulation which both retainsbiological activity while also promoting maximal stability duringstorage within an acceptable temperature range.

The antagonist-based pharmaceutically acceptable composition may be inliquid or solid form. Any technique for production of liquid or solidformulations may be utilized. Such techniques are well within the realmof the abilities of the skilled artisan. Solid formulations may beproduced by any available method including, but not limited to,lyophilization, spray drying, or drying by supercritical fluidtechnology. Solid formulations for oral administration may be in anyform rendering the antagonist accessible to the patient in theprescribed amount and within the prescribed period of time. The oralformulation can take the form of a number of solid formulationsincluding, but not limited to, a tablet, capsule, or powder. Solidformulations may alternatively be lyophilized and brought into solutionprior to administration for either single or multiple dosing. Antagonistcompositions should generally be formulated within a biologicallyrelevant pH range and may be buffered to maintain a proper pH rangeduring storage. Both liquid and solid formulations generally requirestorage at lower temperatures (e.g., 2-8° C.) in order to retainstability for longer periods. Formulated antagonist compositions,especially liquid formulations, may contain a bacteriostat to prevent orminimize proteolysis during storage, including but not limited toeffective concentrations (e.g., ≦1% w/v) of benzyl alcohol, phenol,m-cresol, chlorobutanol, methylparaben, and/or propylparaben. Abacteriostat may be contraindicated for some patients. Therefore, alyophilized formulation may be reconstituted in a solution eithercontaining or not containing such a component. Additional components maybe added to either a buffered liquid or solid antagonist formulation,including but not limited to sugars as a cryoprotectant (including butnot limited to polyhydroxy hydrocarbons such as sorbitol, mannitol,glycerol, and dulcitol and/or disaccharides such as sucrose, lactose,maltose, or trehalose) and, in some instances, a relevant salt(including but not limited to NaCl, KCl, or LiCl). Such antagonistformulations, especially liquid formulations slated for long termstorage, will rely on a useful range of total osmolarity to both promotelong term stability at temperatures of, for example, 2-8° C. or higher,while also making the formulation useful for parenteral injection. Asappropriate, preservatives, stabilizers, buffers, antioxidants and/orother additives may be included. The formulations may contain a divalentcation (including but not limited to MgCl2, CaCl2, and MnCl2); and/or anon-ionic surfactant (including but not limited to Polysorbate-80 (Tween80™), Polysorbate-60 (Tween 60™), Polysorbate-40 (Tween 40™), andPolysorbate-20 (Tween 20™), polyoxyethylene alkyl ethers, including butnot limited to Brij 58™, Brij 35™, as well as others such as TritonX-100™, Triton X-114™, NP40™, Span 85 and the Pluronic series ofnon-ionic surfactants (e.g., Pluronic 121)). Any combination of suchcomponents form specific embodiments of the present invention.

Pharmaceutical compositions in liquid format may include a liquidcarrier, e.g., water, petroleum, animal oil, vegetable oil, mineral oil,or synthetic oil. The liquid format may also include physiologicalsaline solution, dextrose or other saccharide solution or glycols, suchas ethylene glycol, propylene glycol or polyethylene glycol.

Preferably, the pharmaceutical composition may be in the form of aparenterally acceptable aqueous solution that is pyrogen-free withsuitable pH, tonicity, and stability. Pharmaceutical compositions may beformulated for administration after dilution in isotonic vehicles, forexample, Sodium Chloride Injection, Ringer's Injection, or LactatedRinger's Injection.

Dosing of antagonist therapeutics is well within the realm of theskilled artisan, see, e.g., Lederman et al., 1991 Int. J. Cancer47:659-664; Bagshawe et al., 1991 Antibody, Immunoconjugates andRadiopharmaceuticals 4:915-922, and will vary based on a number offactors including but not limited to the particular PCSK9-specificantagonist utilized, the patient being treated, the condition of thepatient, the area being treated, the route of administration, and thetreatment desired. A physician or veterinarian of ordinary skill canreadily determine and prescribe the effective therapeutic amount of theantagonist. Dosage ranges may be from about 0.01 to 100 mg/kg, and moreusually 0.05 to 25 mg/kg, of the host body weight. For example, dosagescan be 0.3 mg/kg body weight, 1 mg/kg body weight, 3 mg/kg body weight,5 mg/kg body weight or 10 mg/kg body weight or within the range of 1-10mg/kg. For purposes of illustration, and not limitation, in specificembodiments, a dose of 5 mg to 2.0 g may be utilized to deliver theantagonist systemically. Optimal precision in achieving concentrationsof antagonist within a range that yields efficacy without toxicityrequires a regimen based on the kinetics of the drug's availability tothe target site(s). This involves a consideration of the distribution,equilibrium, and elimination of the PCSK9-specific antagonist.Antagonists described herein may be used alone at appropriate dosages.Alternatively, co-administration or sequential administration of otheragents may be desirable. It will be possible to present a therapeuticdosing regime for the PCSK9-specific antagonists of the presentinvention in conjunction with alternative treatment regimes. Forexample, PCSK9-specific antagonists may be used in combination or inconjunction with other cholesterol-lowering drugs, including, but notlimited to, cholesterol absorption inhibitors (e.g., Zetia™) andcholesterol synthesis inhibitors (e.g., Zocor™ and Vytorin™).Individuals (subjects) capable of treatment include primates, human andnon-human, and include any non-human mammal or vertebrate of commercialor domestic veterinary importance.

The PCSK9-specific antagonist may be administered to an individual byany route of administration appreciated in the art, including but notlimited to oral administration, administration by injection (specificembodiments of which include intravenous, subcutaneous, intraperitonealor intramuscular injection), administration by inhalation, intranasal,or topical administration, either alone or in combination with otheragents designed to assist in the treatment of the individual. The routeof administration should be determined based on a number ofconsiderations appreciated by the skilled artisan including, but notlimited to, the desired physiochemical characteristics of the treatment.Treatment may be provided on a daily, weekly, biweekly, or monthlybasis, or any other regimen that delivers the appropriate amount ofPCSK9-specific antagonist to the individual at the prescribed times suchthat the desired treatment is effected and maintained. The formulationsmay be administered in a single dose or in more than one dose atseparate times.

In particular embodiments, the condition treated is selected from thegroup consisting of: hypercholesterolemia, coronary heart disease,metabolic syndrome, acute coronary syndrome and related conditions. Useof a PCSK9-specific antagonist in the manufacture of a medicament fortreatment of a PCSK9-associated condition or, alternatively a conditionthat could stand to benefit from a PCSK9 antagonist, including thosespecified above, therefore, forms an important embodiment of the presentinvention.

The present invention further provides for the administration ofdisclosed anti-PCSK9 antagonists for purposes of gene therapy. Throughsuch methods, cells of a subject are transformed with nucleic acidencoding a PCSK9-specific antagonist of the invention. Subjectscomprising the nucleic acids then produce the PCSK9-specific antagonistsendogenously. Previously, Alvarez, et al, Clinical Cancer Research6:3081-3087, 2000, introduced single-chain anti-ErbB2 antibodies tosubjects using a gene therapy approach. The methods disclosed byAlvarez, et al, supra, may be easily adapted for the introduction ofnucleic acids encoding an anti-PCSK9 antibody of the invention to asubject.

Nucleic acids encoding any PCSK9-specific antagonist may be introducedto a subject.

The nucleic acids may be introduced to the cells of a subject by anymeans known in the art. In preferred embodiments, the nucleic acids areintroduced as part of a viral vector. Examples of preferred viruses fromwhich the vectors may be derived include lentiviruses, herpes viruses,adenoviruses, adeno-associated viruses, vaccinia virus, baculovirus,alphavirus, influenza virus, and other recombinant viruses withdesirable cellular tropism.

Various companies produce viral vectors commercially, including, but byno means limited to, Avigen, Inc. (Alameda, Calif.; AAV vectors), CellGenesys (Foster City, Calif.; retroviral, adenoviral, AAV vectors, andlentiviral vectors), Clontech (retroviral and baculoviral vectors),Genovo, Inc. (Sharon Hill, Pa.; adenoviral and AAV vectors), Genvec(adenoviral vectors), IntroGene (Leiden, Netherlands; adenoviralvectors), Molecular Medicine (retroviral, adenoviral, AAV, and herpesviral vectors), Norgen (adenoviral vectors), Oxford BioMedica (Oxford,United Kingdom; lentiviral vectors), and Transgene (Strasbourg, France;adenoviral, vaccinia, retroviral, and lentiviral vectors).

Methods for constructing and using viral vectors are known in the art(see, e.g., Miller, et al, BioTechniques 7:980-990, 1992). Preferably,the viral vectors are replication defective, that is, they are unable toreplicate autonomously, and thus are not infectious, in the target cell.Preferably, the replication defective virus is a minimal virus, i.e., itretains only the sequences of its genome which are necessary forencapsidating the genome to produce viral particles. Defective viruses,which entirely or almost entirely lack viral genes, are preferred. Useof defective viral vectors allows for administration to cells in aspecific, localized area, without concern that the vector can infectother cells. Thus, a specific tissue can be specifically targeted.

Examples of vectors comprising attenuated or defective DNA virussequences include, but are not limited to, a defective herpes virusvector (Kanno et al, Cancer Gen. Ther. 6:147-154, 1999; Kaplitt et al,J. Neurosci. Meth. 71:125-132, 1997 and Kaplitt et al, J. Neuro Onc.19:137-147, 1994).

Adenoviruses are eukaryotic DNA viruses that can be modified toefficiently deliver a nucleic acid of the invention to a variety of celltypes. Attenuated adenovirus vectors, such as the vector described byStrafford-Perricaudet et al, J. Clin. Invest. 90:626-630, 1992 aredesirable in some instances. Various replication defective adenovirusand minimum adenovirus vectors have been described (PCT Publication Nos.WO94/26914, WO94/28938, WO94/28152, WO94/12649, WO95/02697 andWO96/22378). The replication defective recombinant adenovirusesaccording to the invention can be prepared by any technique known to aperson skilled in the art (Levrero et al, Gene 101:195, 1991; EP 185573;Graham, EMBO J. 3:2917, 1984; Graham et al, J. Gen. Virol. 36:59, 1977).

The adeno-associated viruses (AAV) are DNA viruses of relatively smallsize which can integrate, in a stable and site-specific manner, into thegenome of the cells which they infect. They are able to infect a widespectrum of cells without inducing any effects on cellular growth,morphology or differentiation, and they do not appear to be involved inhuman pathologies. The use of vectors derived from the AAVs fortransferring genes in vitro and in vivo has been described (see Daly, etal, Gene Ther. 8:1343-1346, 2001, Larson et al, Adv. Exp. Med. Bio.489:45-57, 2001; PCT Publication Nos. WO 91/18088 and WO 93/09239; U.S.Pat. Nos. 4,797,368 and 5,139,941 and EP 488528B1).

In another embodiment, the gene can be introduced in a retroviralvector, e.g., as described in U.S. Pat. Nos. 5,399,346, 4,650,764,4,980,289, and 5,124,263; Mann et al, Cell 33:153, 1983; Markowitz etal, J. Virol., 62:1120, 1988; EP 453242 and EP178220. The retrovirusesare integrating viruses which infect dividing cells.

Lentiviral vectors can be used as agents for the direct delivery andsustained expression of nucleic acids encoding a PCSK9-specificantagonist of the invention in several tissue types, including brain,retina, muscle, liver and blood. The vectors can efficiently transducedividing and nondividing cells in these tissues, and maintain long-termexpression of the PCSK9-specific antagonist. For a review, see Zuffereyet al, J. Virol. 72:9873-80, 1998 and Kafri et al, Curr. Opin. Mol.Ther. 3:316-326, 2001. Lentiviral packaging cell lines are available andknown generally in the art. They facilitate the production of high-titerlentivirus vectors for gene therapy. An example is atetracycline-inducible VSV-G pseudotyped lentivirus packaging cell linewhich can generate virus particles at titers greater than 10⁶ IU/ml forat least 3 to 4 days; see Kafri et al, J. Virol. 73:576-584, 1999. Thevector produced by the inducible cell line can be concentrated as neededfor efficiently transducing nondividing cells in vitro and in vivo.

Sindbis virus is a member of the alphavirus genus and has been studiedextensively since its discovery in various parts of the world beginningin 1953. Gene transduction based on alphavirus, particularly Sindbisvirus, has been well-studied in vitro (see Straus et al, Microbial.Rev., 58:491-562, 1994; Bredenbeek et al, J. Virol., 67:6439-6446, 1993;Ijima et al, Int. J. Cancer 80:110-118, 1999 and Sawai et al, Biochim.Biophyr. Res. Comm. 248:315-323, 1998. Many properties of alphavirusvectors make them a desirable alternative to other virus-derived vectorsystems being developed, including rapid engineering of expressionconstructs, production of high-titered stocks of infectious particles,infection of nondividing cells, and high levels of expression (Strausset al, 1994 supra). Use of Sindbis virus for gene therapy has beendescribed. (Wahlfors et al, Gene. Ther. 7:472-480, 2000 and Lundstrom,J. Recep. Sig. Transduct. Res. 19(1-4):673-686, 1999.

In another embodiment, a vector can be introduced to cells bylipofection or with other transfection facilitating agents (peptides,polymers, etc.). Synthetic cationic lipids can be used to prepareliposomes for in vivo and in vitro transfection of a gene encoding amarker (Feigner et al, Proc. Natl. Acad. Sci. USA 84:7413-7417, 1987 andWang et al, Proc. Natl. Acad. Sci. USA 84:7851-7855, 1987). Useful lipidcompounds and compositions for transfer of nucleic acids are describedin PCT Publication Nos. WO 95/18863 and WO 96/17823, and in U.S. Pat.No. 5,459,127.

It is also possible to introduce the vector in vivo as a naked DNAplasmid. Naked DNA vectors for gene therapy can be introduced intodesired host cells by methods known in the art, e.g., electroporation,microinjection, cell fusion, DEAE dextran, calcium phosphateprecipitation, use of a gene gun, or use of a DNA vector transporter(see, e.g., Wilson, et al, J. Biol. Chem. 267:963-967, 1992; Williams etal, Proc. Natl. Acad. Sci. USA 88:2726-2730, 1991). Other reagentscommonly used for transfection of plasmids include, but are by no meanslimited to, FuGene, Lipofectin, and Lipofectamine. Receptor-mediated DNAdelivery approaches can also be used (Wu et al, J. Biol. Chem.263:14621-14624, 1988). U.S. Pat. Nos. 5,580,859 and 5,589,466 disclosedelivery of exogenous DNA sequences, free of transfection facilitatingagents, in a mammal. Recently, a relatively low voltage, high efficiencyin vivo DNA transfer technique, termed electrotransfer, has beendescribed (Vilquin et al, Gene Ther. 8:1097, 2001; Payen et al, Exp.Hematol. 29:295-300, 2001; Mir, Bioelectrochemistry 53:1-10, 2001; PCTPublication Nos. WO 99/01157, WO 99/01158 and WO 99/01175).

Pharmaceutical compositions suitable for such gene therapy approachesand comprising nucleic acids encoding an anti-PCSK9 antagonist of thepresent invention are included within the scope of the presentinvention.

In another aspect, the present invention provides a method foridentifying, isolating, quantifying or antagonizing PCSK9 in a sample ofinterest using a PCSK9-specific antagonist of the present invention. ThePCSK9-specific antagonists may be utilized as research tools inimmunochemical assays, such as Western blots, ELISAs, radioimmunoassay,immunohistochemical assays, immunoprecipitations, or otherimmunochemical assays known in the art (see, e.g., ImmunologicalTechniques Laboratory Manual, ed. Goers, J. 1993, Academic Press) orvarious purification protocols. The antagonists may have a labelincorporated therein or affixed thereto to facilitate readyidentification or measurement of the activities associated therewith.One skilled in the art is readily familiar with the various types ofdetectable labels (e.g., enzymes, dyes, or other suitable moleculeswhich are either readily detectable or cause some activity/result thatis readily detectable) which are or may be useful in the aboveprotocols.

An additional aspect of the present invention are kits comprisingPCSK9-specific antagonists or pharmaceutical compositions disclosedherein and instructions for use. Kits typically but need not include alabel indicating the intended use of the contents of the kit. The termlabel includes any writing, or recorded material supplied on or with thekit, or which otherwise accompanies the kit.

The present invention also relates to a method for identifyingPCSK9-specific antagonists in a cell sample which comprises providingpurified PCSK9 (or functional equivalent) and labeled LDL particles to acell sample; providing a molecule(s) suspected of being a PCSK9antagonist to the cell sample; incubating said cell sample for a periodof time sufficient to allow LDL particle uptake by the cells;quantifying the amount of label incorporated into the cell; andidentifying those candidate antagonists that result in an increase inthe amount of quantified label as compared with that observed when PCSK9(or functional equivalent) is administered alone. The present inventionalso relates to a method for identifying PCSK9-specific antagonists in acell sample which comprises providing purified PCSK9 (or functionalequivalent) and labeled LDL particles to a cell sample; providing amolecule(s) suspected of being a PCSK9 antagonist to the cell sample;incubating said cell sample for a period of time sufficient to allow LDLparticle uptake by the cells; isolating cells of the cell sample byremoving the supernate; reducing non-specific association of labeled LDLparticles (whether to the plate, the cells, or anything other than theLDL receptor); lysing the cells; quantifying the amount of labelretained within the cell lysate; and identifying those candidateantagonists that result in an increase in the amount of quantified labelas compared with that observed when PCSK9 is administered alone.Candidate antagonists that result in an increase in the amount ofquantified label are PCSK9 antagonists. This method has proven to be aneffective means for identifying PCSK9-specific antagonists and, thus,forms an important aspect of the present invention. Any type of cellbearing the LDL receptor can be employed in the disclosed methodincluding, but not limited to HEK cells, HepG2 cells, and CHO cells. A“functional equivalent” of PCSK9 is defined herein as a protein with atleast 80% homology to PCSK9 at the amino acid level having eitherconservative amino acid substitutions or modifications thereto; saidprotein which exhibits measurable inhibition of LDL uptake by the LDLreceptor. Nucleic acid encoding said protein would hybridize to thecomplement of nucleic acid encoding PCSK9 under stringent hybridizationconditions. Any number of cells can be plated. For purposes ofexemplification, the current methods plated 30,000 cells/well in a 96well plate. In preferred embodiments, the cells are in serum-free mediawhen the PCSK9 (or functional equivalent) is added. In specificembodiments, the cells are plated for a period of time (e.g., ˜24 hours)in media with serum; subsequently plated in serum-free media (havingremoved the serum-containing media) for a period of time (e.g., ˜24hours); prior to addition of the purified PCSK9 (or functionalequivalent) and labeled LDL particles. The step of reducing non-specificassociation of labeled LDL particles is typically carried out by awashing/rinsing step(s) albeit, as the skilled artisan is aware, anytechnique(s) of accomplishing reduction of non-specific association maybe utilized. LDL particles derived from any source are of use in theabove-described assays. In preferred embodiments, the LDL particles arefresh particles derived from blood. This can be accomplished by anymethod available to the skilled artisan including, but not limited to,the method of Havel et al., 1955 J. Clin. Invest. 34: 1345-1353. Inspecific embodiments, the LDL particles are labeled with fluorescence.In particular embodiments, the labeled LDL particles have incorporatedtherein visible wavelength excited fluorophore3,3′-dioctadecylindocarbocyanine iodide (dil(3)) to form the highlyfluorescent LDL derivative dil(3)-LDL. As recognized by one skilled inthe art, the present invention can be practiced with any label whichenables the skilled artisan to detect LDL in the cellular lysate. Inspecific embodiments, an LDL analog may be used that would only becomedetectable (e.g., become fluorescent or fluoresce at a differentwavelength, etc.) when metabolized intracellularly or, for instance, ifit were to become associated with (or dissociated from) other moleculesin the process of becoming internalized (e.g. a FRET assay, in which anLDL analog would become associated with a secondary fluor, or else bedissociated from a quencher). Any means available in the art fordetecting internalization of labeled LDL particles can be employed inthe present invention. The incubation time for the LDL particles andPCSK9 with the cells is an amount of time sufficient to allow LDLparticle uptake by the cells. In specific embodiments, this time iswithin the range of 5 minutes to 360 minutes. In specific embodiments,the concentration of PCSK9 or functional equivalent added to the cellsis in the range of 1 nM to 5 μM. In more specific embodiments, theconcentration of PCSK9 or functional equivalent added to the cells is inthe range of 0.1 nM to 3 μM. One specific means by which the skilledartisan can determine a range of concentrations for a particular PCSK9protein is to develop a dose response curve in the LDL-uptake assay. Aconcentration of PCSK9 can be selected that promotes close to maximalloss of LDL-uptake and is still in the linear range of the dose responsecurve. Typically, this concentration is ˜5 times the EC-50 of theprotein extracted from the dose response curve. The concentrations canvary by protein. For purposes of exemplification, the amount ofwild-type PCSK9 used in Example 5 was ˜320 nM, whereas, in equivalentassays employing “gain of function” PCSK9s (e.g., S127R and D374Y), saidmutants were added at a lower concentration (e.g., 6-50 nM). In thedescribed assay, cells are typically maintained at a temperaturesuitable for their maintenance and/or growth. In specific embodiments,the temperature is maintained around 37° C.

The following examples are provided to illustrate the present inventionwithout limiting the same hereto:

Example 1 Isolation of Recombinant Fab Display Phage

Recombinant Fab phage display libraries (see, e.g., Knappik et al., 2000J. Mol. Biol. 296:57-86) were panned against immobilized recombinanthuman PCSK9 through a process which is briefly described as follows:Phage Fab display libraries were first divided into 3 pools: one pool ofVH2+VH4+VH5, another of VH1+VH6, and a third pool of VH3. The phagepools and immobilized PCSK9 protein were blocked with nonfat dry milk.

For the first round of panning, each phage pool was bound independentlyto V5-, His-tagged PCSK9 protein immobilized in wells of Nunc Maxisorpplate. Immobilized phage-PCSK9 complexes were washed sequentially with(1) PBS/0.5% Tween™ 20 (Three quick washes); (2) PBS/0.5% Tween™ 20 (One5 min. incubation with mild shaking); (3) PBS (Three quick washes); and(4) PBS (Two 5-min. incubations with mild shaking). Bound phages wereeluted with 20 mM DTT and all three eluted phage suspensions werecombined into one tube. E. coli TG1 were infected with eluted phages.Pooled culture of phagemid-bearing cells (chloramphenicol-resistant)were grown up and frozen stock of phagemid-bearing culture were made.Phage were rescued from culture by co-infection with helper phage, andphage stock for next round of panning were made.

For the second round of panning, phages from Round 1 were bound toimmobilized, blocked V5-, His-tagged PCSK9 protein. Immobilizedphage-PCSK9 complexes were washed sequentially with (1) PBS/0.05% Tween™20 (One quick wash); (2) PBS/0.05% Tween™ 20 (Four 5 min. incubationswith mild shaking); (3) PBS (One quick wash); and (4) PBS (Four 5-min.incubations with mild shaking). Bound phages were eluted, E. coli TG1cells were infected, and phage were rescued as in Round 1.

For the third round of panning, phages from Round 2 were bound toimmobilized, blocked V5-His-tagged PCSK9 protein. Immobilizedphage-PCSK9 complexes were washed sequentially with (1) PBS/0.05% Tween™20 (Ten quick washes); (2) PBS/0.05% Tween™ 20 (Five 5 min. incubationswith mild shaking); (3) PBS (Ten quick washes); and (4) PBS (Five 5-min.incubations with mild shaking). Bound phages were eluted and E. coli TG1cells were infected as in Round 1. Phagemid-infected cells were grownovernight and phagemid DNA was prepared.

XbaI-EcoRI inserts from Round 3 phagemid DNA were subcloned intoMorphosys Fab expression vector pMORPH_x9_MH (see, e.g., FIG. 1), and alibrary of Fab expression clones was generated in E. coli TG1 F−.Transformants were spread on LB+chloramphenicol+glucose plates and grownovernight to generate bacterial colonies. Individual transformantcolonies were picked and placed into wells of two 96-well plates forgrowth and screening for Fab expression.

Example 2 Elisa Screening of Bacterially Expressed Fabs

Cultures of individual transformants were IPTG-induced and grownovernight for Fab expression. Culture supernatants (candidate Fabs) wereincubated with purified V5-, His-tagged PCSK9 protein immobilized inwells of 96-well Nunc Maxisorp plates, washed with 0.1% Tween™ 20 in PBSusing a plate washer, incubated with HRP-coupled anti-Fab antibody, andwashed again with PBS/Tween™ 20. Bound HRP was detected by addition ofTMP substrated, and A₄₅₀ values of wells were read with a plate reader.

Negative controls were included as follows:

Controls for nonspecific Fab binding on each plate were incubated withparallel expressed preparations of anti-EsB, an irrelevant Fab.Growth medium only.

Positive controls for ELISA and Fab expression were included as follows:EsB antigen was bound to three wells of the plate and subsequentlyincubated with anti-EsB Fab. To control for Fabs reacting with the V5 orHis tags of the recombinant PCSK9 antigen, parallel ELISAs wereperformed using V5-, His-tagged secreted alkaline phosphatase protein(SEAP) expressed in the same cells as the original PCSK9 antigen andsimilarly purified. Putative PCSK9-reactive Fabs were identified asyielding >3× background values when incubated with PCSK9 antigen butnegative when incubated with SEAP. Clones scoring as PCSK9-reactive inthe first round of screening were consolidated onto a single plate,re-grown in triplicate, re-induced with IPTG, and re-assayed in parallelELISAs vs. PCSK9 and SEAP. Positive and negative controls were includedas described above. Clones scoring positive in at least 2 of 3replicates were carried forward into subsequent characterizations. Incases of known or suspected mixed preliminary clones, cultures werere-purified by streaking for single colonies on 2×YT plates withchloramphenicol, and liquid cultures from three or more separatecolonies were assayed again by ELISAs in triplicate as described above.

Example 3 DNA Sequence Determination of PCSK9 ELISA-Positive Fab Clones

Bacterial culture for DNA preps were made by inoculating 1.2 ml 2×YTliquid media with chloramphenicol from master glycerol stocks ofpositive Fabs, and growing overnight. DNA was prepared from cell pelletscentrifuged out of the overnight cultures using the Qiagen Turbo Minipreps performed on a BioRobot 9600. ABI Dye Terminator cycle sequencingwas performed on the DNA with Morphosys defined sequencing primers andrun on an ABI 3100 Genetic Analyzer, to obtain the DNA sequence of theFab clones. DNA sequences were compared to each other to determineunique clone sequences and to determine light and heavy chain subtypesof the Fab clones.

Example 4 Expression and Purification of Fab's from Unique PCSK9ELISA-Positive Clones

Fabs from ELISA-positive clones (1CX1G08, 3BX5C01, 3CX2A06, 3CX3D02 and3CX4B08) and the EsB (negative control) Fab were expressed byIPTG-induction in E. coli TG1F− cells. Cultures were lysed and theHis-tagged Fabs were purified by immobilized metal ion affinitychromatography (IMAC), and proteins were exchanged into 25 mM HEPES pH7.3/150 mM NaCl by centrifugal diafiltration. Proteins were analyzed byelectrophoresis on Caliper Lab-Chip 90 and by conventional SDS-PAGE, andquantified by Bradford protein assay. Purified Fab protein wasre-assayed by ELISA in serial dilutions to confirm activity of purifiedFab. Positive and Negative controls were run as before. Purified Fabpreparations were analyzed in the EXOPOLAR (cholesterol uptake) assaydescribed below.

Example 5 Exopolar Assay Effects of Exogenous PCSK9 on Cellular LDLUptake

On day 1, 30,000 cells/well were plated in a 96 well polyD-lysine coatedplate. On day 2, the media was switched to no-serum containing DMEMmedia. On day 3, the media was removed and the cells were washed withOptiMEM. Purified PCSK9 was added in 100 μl of DMEM media containingLPDS and dI-LDL. The plates were incubated at 37° C. for 6.5 hrs. Thecells were washed quickly in TBS containing 2 mg/ml BSA; then washed inTBS-BSA for 2 minutes; and then washed twice (but quickly) with TBS. Thecells were lysed in 100 μl RIPA buffer. Fluorescence was then measuredin the plate using an Ex 520, Em 580 nm. The total cellular protein ineach well was measured using a BCA Protein Assay and the fluorescenceunits were then normalized to total protein.

The Exopolar Assay is effective for characterizing variant effects onLDL uptake; see FIG. 2 illustrating how the potencies of PCSK9 mutantscorrelate with plasma LDL-cholesterol in the Exopolar Assay. The data istabulated as follows:

TABLE 2 EC-50 (nM) Mutation Gain/Loss LDL-C (mg/dI) Exopolar S127R Gain277 14 D374Y Gain 388 1.3 Wild-type 140 51 R46L Loss 116 78

Results: Five antibody molecules (1CX1G08; 3BX5C01; 3CX2A06; 3CX3D02;and 3CX4B08) dose-dependently inhibited the effects of PCSK9 on LDLuptake; an effect which was reproducibly observed. The amount of PCSK9added to the cells was ˜320 nM. The antibody molecules comprise asfollows: (a) 1CX1G08, a LC chain of SEQ ID NO: 1 (comprising a VL of SEQID NO: 93), and a Fd chain of SEQ ID NO: 9 (comprising a VH of SEQ IDNO: 11); (b) 3BX5C01, a LC chain of SEQ ID NO: 19 (comprising a VL ofSEQ ID NO: 95), and a Fd chain of SEQ ID NO: 25 (comprising a VH of SEQID NO: 27); (c) 3CX2A06, a LC chain of SEQ ID NO: 35 (comprising a VL ofSEQ ID NO: 97), and a Fd chain of SEQ ID NO: 43 (comprising a VH of SEQID NO: 45); (d) 3CX3D02, a LC chain of SEQ ID NO: 53 (comprising a VL ofSEQ ID NO: 99), and a Fd chain of SEQ ID NO: 59 (comprising a VH of SEQID NO: 61); and (e) 3CX4B08, a LC chain of SEQ ID NO: 69 (comprising aVL of SEQ ID NO: 101), and a Fd chain of SEQ ID NO: 77 (comprising a VHof SEQ ID NO: 79). FIGS. 3A-3D illustrate 1CX1G08's and 3CX4B08'sdose-dependent inhibition of PCSK9-dependent effects on LDL uptake.FIGS. 3B and 3D have two controls: (i) a cell only control, showing thebasal level of cellular LDL uptake, and (ii) a cell+PCSK9 (25 μg/ml)control which shows the level of PCSK9-dependent loss of LDL-uptake. Thetitration experiments which contain Fab and PCSK9 were done at a fixedconcentration of PCSK9 (25 μg/ml) and increasing concentrations of Fabshown in the graphs. FIGS. 3A and 3C show calculations of IC-50s.1CX1G08 exhibited a 53% inhibition of PCSK9-dependent inhibition ofcellular LDL uptake, while 3CX4B08 exhibited a 61% inhibition. FIGS.4A-4D illustrate 3BX5C01's and 3CX2A06's dose-dependent inhibition ofPCSK9-dependent effects on LDL uptake. FIGS. 4B and 4D have twocontrols: (i) a cell only control, showing the basal level of cellularLDL uptake, and (ii) a cell+PCSK9 (25 μg/ml) control which shows thelevel of PCSK9-dependent loss of LDL-uptake. The titration experimentswhich contain Fab and PCSK9 were done at a fixed concentration of PCSK9(25 μg/ml) and increasing concentrations of Fab shown in the graphs.FIGS. 4A and 4C show calculations of IC-50s. 3BX5C01 exhibited a 25%inhibition of PCSK9-dependent inhibition of cellular LDL uptake, while3CX2A06 exhibited 23% inhibition. FIGS. 5A-5B illustrate 3CX3D02'sdose-dependent inhibition of PCSK9-dependent effects on LDL uptake. FIG.5B has two controls: (i) a cell only control, showing the basal level ofcellular LDL uptake, and (ii) a cell+PCSK9 (25 μg/ml) control whichshows the level of PCSK9-dependent loss of LDL-uptake. The titrationexperiment which contains Fab and PCSK9 was done at a fixedconcentration of PCSK9 (25 μg/ml) and increasing concentrations of Fabshown in the graphs. FIG. 5A shows calculations of IC-50. 3CX3D02exhibited a 23% inhibition of PCSK9-dependent inhibition of cellular LDLuptake.

Example 6 Kinetic Evaluation of Fab:PCSK9 Interactions with SurfacePlasmon Resonance (“SPR”)

SPR measurements were performed using a Biacore™ (Pharmacia BiosensorAB, Uppsala, Sweden) 2000 system. Sensor chip CM5 and Amine coupling kitfor immobilization were from Biacore™.

Anti-Fab IgG (Human specific) was covalently coupled to surfaces 1 and 2of a Sensor Chip CM5 via primary amine groups, using the immobilizationwizard with the “Aim for immobilization” option. A target immobilizationof 5000 RU was specified. The wizard uses a 7 minute activation with a1:1 mixture of 100 mM NHS and 400 mM EDC; injects the ligand in severalpulses to achieve the desired level, then deactivates the remainingsurface with a 7 minute pulse of ethanolamine.

Anti-PCSK9 Fabs were captured on capture surface 2 and surface 1 wasused as a reference for kinetic studies of Fab:PCSK9 interactions. Fabwas captured by flowing a 500 ng/ml solution at 5 μl/min for 1-1.5minutes to reach a target R_(L) for an R_(max) of 100-150 RU for thereaction. 5-10 concentrations of hPCSK9v5His or mPCSK9v5His antigenswere flowed across the surface at 30 μl/minute for 3-4 minutes. 15-60minutes dissociation time was allowed before regeneration of theAnti-Fab surface with a 30 second pulse of 10 mM glycine pH 2.0.

BiaEvaluation Software was used to evaluate the sensograms from themultiple concentration of PCSK9 antigen analyzed with each Fab, toestimate the kinetics constants of the Fab:PCSK9 interactions.

Table 3 illustrates kinetic parameters measured for disclosed anti-PCSK9Fabs:

TABLE 3 Fab Ag Method k_(on) (1/Ms × 10⁻⁵) K_(off) (1/s × 10⁴) K_(D)(nM) 1CX1G08 hPCSK9 Direct & Ab 3.35 ± 0.86 1.76 ± 0.13  0.55 ± 0.18mean Capture* (N = 3) 3BX5C01 hPCSK9 Direct* 0.28 ± 0.00 6.42 ± 1.6123.07 ± 5.6 mean (N = 2) 3CX3D02 hPCSK9 Direct* 1.66 ± 1.24 8.76 ± 1.02 7.01 ± 4.63 mean (N = 2) 3CX4B08 hPCSK9 Direct & Ab 2.33 ± 0.55 6.85 ±3.13  2.97 ± 1.46 mean Capture* (N = 3) *“Direct” = covalentimmobilization of PCSK9; bind Fab from mobile phase. “Ab Capture” =covalent immobilization of anti-Fab Ab; capture of test Ab, then bindPCSK9 from mobile phase.

1. An isolated PCSK9-specific antagonist that antagonizes PCSK9'sinhibition of cellular LDL uptake and comprises: (a) a heavy chainvariable region comprising a CDR3 domain comprising SEQ ID NO: 17 or anequivalent thereof characterized as having one or more conservativeamino acid substitutions in the CDR3 domain; and/or (b) a light chainvariable region comprising a CDR3 domain comprising SEQ ID NO: 7 or anequivalent thereof characterized as having one or more conservativeamino acid substitutions in the CDR3 domain.
 2. The PCSK9-specificantagonist of claim 1 that binds to human PCSK9 with an equilibriumdissociation constant (KD) of less than 1200 nM.
 3. The PCSK9-specificantagonist of claim 1 that binds to human PCSK9 with a KD of less than500 nM.
 4. The PCSK9-specific antagonist of claim 1 that binds to humanPCSK9 with a KD of less than 100 nM.
 5. The PCSK9-specific antagonist ofclaim 1 that binds to human PCSK9 with a KD of less than 5 nM.
 6. ThePCSK9-specific antagonist of claim 1 that antagonizes PCSK9's inhibitionof cellular LDL uptake at an IC50 of less than 500 nM.
 7. ThePCSK9-specific antagonist of claim 1 that antagonizes PCSK9's inhibitionof cellular LDL uptake at an IC50 of less than 200 nM.
 8. ThePCSK9-specific antagonist of claim 1 that antagonizes PCSK9's inhibitionof cellular LDL uptake at an IC50 of less than 100 nM.
 9. ThePCSK9-specific antagonist of claim 1 that antagonizes PCSK9's inhibitionof cellular uptake by at least 20%.
 10. An isolated PCSK9-specificantagonist that antagonizes PCSK9's inhibition of cellular uptake andcomprises: (a) a heavy chain variable region comprising a CDR3 domaincomprising SEQ ID NO: 17 or an equivalent thereof characterized ashaving one or more conservative amino acid substitutions in the CDR3domain; and/or (b) a light chain variable region comprising a CDR3domain comprising SEQ ID NO: 7 or an equivalent thereof characterized ashaving one or more conservative amino acid substitutions in the CDR3domain; wherein said PCSK9-specific antagonist is an antibody molecule;and wherein said PCSK9-specific antagonist antagonizes PCSK9'sinhibition of cellular uptake by at least 20%.
 11. The PCSK9-specificantagonist of claim 10 which comprises: (a) a heavy chain variable CDR1sequence comprising SEQ ID NO: 13; (b) a heavy chain variable CDR2sequence comprising SEQ ID NO: 15; (c) a light chain variable CDR1sequence comprising SEQ ID NO:3; and/or (d) a light chain variable CDR2sequence comprising SEQ ID NO:
 5. 12. The PCSK9-specific antagonist ofclaim 10 which comprises a heavy chain variable region comprising SEQ IDNO: 11 and/or a light chain variable region comprising SEQ ID NO: 93.13. The PCSK9-specific antagonist of claim 10 which comprises a heavychain region comprising SEQ ID NO: 9 and/or a light chain regioncomprising SEQ ID NO:
 1. 14. The PCSK9-specific antagonist of claim 10which comprises a heavy chain comprising constant sequence comprising:SEQ ID NO:
 87. 15. A composition comprising the PCSK9-specificantagonist of claim 1 and a pharmaceutically acceptable carrier.
 16. Amethod for antagonizing PCSK9 function which comprises employing aPCSK9-specific antagonist of claim
 1. 17. Use of a PCSK9-specificantagonist of claim 1 in the manufacture of a medicament forameliorating a disorder, condition or disease caused and/or exacerbatedby PCSK9 function.
 18. Isolated nucleic acid encoding a PCSK9-specificantagonist of claim
 1. 19. Isolated nucleic acid which encodes aPCSK9-specific antagonist of claim 1 which comprises: (a) a heavy chainvariable region wherein the CDR3 domain is encoded by nucleic acidsequence comprising SEQ ID NO: 18; and/or (b) a light chain variableregion wherein the CDR3 domain is encoded by nucleic acid sequencecomprising SEQ ID NO:
 8. 20. The isolated nucleic acid of claim 19 whichencodes an antibody molecule which comprises: (a) a heavy chain variableregion; said heavy chain variable region which comprises CDR1 and/orCDR2 domains, respectively, encoded by nucleic acid sequence comprisingat least one nucleic acid sequence selected from the group consistingof: SEQ ID NO: 14 and SEQ ID NO: 16; and/or (b) a light chain variableregion; said light chain variable region which comprises CDR1 and/orCDR2 domains, respectively, encoded by nucleic acid sequence comprisingat least one nucleic acid sequence selected from the group consistingof: SEQ ID NO: 4 and SEQ ID NO:
 6. 21. The isolated nucleic acid ofclaim 19 which encodes an antibody molecule which comprises: (a) a heavychain variable region wherein the heavy chain variable region is encodedby nucleic acid sequence comprising SEQ ID NO: 12; and/or (b) a lightchain variable region wherein the light chain variable region is encodedby nucleic acid sequence comprising SEQ ID NO:
 94. 22. The isolatednucleic acid of claim 19 which encodes an antibody molecule whichcomprises: (a) a heavy chain region encoded at least in part by nucleicacid which comprises SEQ ID NO: 10; and/or (b) a light chain regionencoded at least in part by nucleic acid which comprises SEQ ID NO: 2.23. A vector comprising nucleic acid of claim
 18. 24. An isolated hostcell or population of host cells in vitro or in situ comprising nucleicacid of claim
 18. 25. A method for producing a PCSK9-specific antagonistwhich comprises: (a) culturing the cell(s) of claim 24 under conditionsappropriate for production of the PCSK9-specific antagonist; and (b)isolating the PCSK9-specific antagonist produced.
 26. An isolated hostcell or population of host cells in vitro or in situ comprising aPCSK9-specific antagonist of claim 1.